The author of the class probably begins the names with the underscore(s) to tell you, “don’t use it”

You can keep away from that with some additional logic. One of the ways is this:

>>> def f(value, seq=[]):
...     seq.append(value)
...     return seq

>>> def f(value, seq=None):
...     if seq is None:
...         seq = []
...     seq.append(value)
...     return seq

>>> def f(value, seq=None):
...     if not seq:
...         seq = []
...     seq.append(value)
...     return seq

>>> f(value=2)
[2]
>>> f(value=4)
[4]
>>> f(value=8)
[8]
>>> f(value=16)
[16]

The Pythonic way is to exploit the fact that zero is interpreted as False in a Boolean context, while all other numbers are considered as True

>>> bool(0)
False
>>> bool(-1), bool(1), bool(20), bool(28.4)
(True, True, True, True)

>>> for item in x:
...     if item:
...         print(item)
... 
1
2
3
4

When you have numeric data, and you need to check if the numbers are equal to zero, you can but don’t have to use the comparison operators == and !=

>>> x = (1, 2, 0, 3, 0, 4)
>>> for item in x:
...     if item != 0:
...         print(item)
... 
1
2
3
4

it’s a good practice to use properties when you can and C++-like getters and setters when you have to

trace and faulthandler modules cover basic tracing

Dutch programmer Guido van Rossum designed Python in 1991, naming it after the British television comedy Monty Python's Flying Circus because he was reading the show's scripts at the time.

Dunder or magic method, are methods that start and end with double _ like __init__ or __str__. This kind of methods are the mechanism we use to interact directly with python's data model

As the name suggests, multiprocessing spawns processes, while multithreading spawns threads. In Python, one process can run several threads. Each process has its proper Python interpreter and its proper GIL. As a result, starting a process is a heftier and more time-consuming undertaking than starting a thread.

supporting this field is extremely easy If you keep raw data, it's just a matter of adding a getter method to the Article class.

@property
def highlights(self) -> Sequence[Highlight]:
    default = [] # defensive to handle older export formats that had no annotations
    jsons = self.json.get('annotations', default)
    return list(map(Highlight, jsons))

query language doesn't necessarily mean a database. E.g. see pandas which is capable of what SQL is capable of, and even more convenient than SQL for our data exploration purposes.

cachew lets you cache function calls into an sqlite database on your disk in a matter of single decorator (similar to functools.lru_cache). The difference from functools.lru_cache is that cached data is persisted between program runs, so next time you call your function, it will only be a matter of reading from the cache.

We only need to use global keyword in a function if we want to do assignments / change them. global is not needed for printing and accessing.

# This function modifies global variable 's' 
def f(): 
    global s 
    print s 
    s = "Look for Geeksforgeeks Python Section"
    print s  

# Global Scope 
s = "Python is great!" 
f() 
print s

The nonlocal keyword is used to work with variables inside nested functions, where the variable should not belong to the inner function. Use the keyword nonlocal to declare that the variable is not local.

def myfunc1():
  x = "John"
  def myfunc2():
    nonlocal x
    x = "hello"
  myfunc2()
  return x

print(myfunc1())

Here, I rewrite this example using the walrus operator

count = fresh_fruit.get('lemon', 0)
if count:
...

if count := fresh_fruit.get('lemon', 0):
...

map, filter and reduce can all operate independently, or be chained together

During each loop of reduce, you can get result of the last loop, and the next element in the array Change the result, then return it for the next loop iteration When you're done, you have the completed collection

This lets you transform each element into something new (or keep it the same) Types don't have to be the same: can return objects, string, numbers - anything!

It loops over the elements, passing each one to a callback function You can return true to include that element in the new array, or false to exclude it

So why are map, filter and reduce useful?

The formula China is using is current total deaths/current confirmed cases.

Each year the flu infects between 2 to 11% of the population. 11The infectiousness of a disease is measured by its R0 value. R0 is a measure of how many people will catch a disease from one infected person. The R0 value of the flu is 1.28. The R0 of COVID-19 is assumed to be between 1.4–3.8

cases outside of china are doubling roughly every 5 days. The reported rate of infection in China is lower, but China has taken drastic quarantine measures, including welding people inside apartment buildings.

“confirmed cases” is the lowest possible number of cases in that country. It’s the lower bound of an estimate.

In The Atlantic, Marc Lipsitch, a leading epidemiologist at Harvard reported that “that within the coming year, some 40 to 70 percent of people around the world will be infected with the virus that causes COVID-19”. This was last week and while ridiculed at the time, his assumptions are now the generally accepted position among epidemiologists.

Death Rate

The Virus may persist on surfaces for up to 9 days, on some surfaces up to 27 days

10-50 minutes in natural spaces was the most effective to improve mood, focus and physiological markers like blood pressure and heart rate. “It’s not that there’s a decline after 50 minutes, but rather that the physiological and self-reported psychological benefits tend to plateau after that,”

Steven Hoober shed light on the three ways users hold their phones.

We’re mapping a human health tragedy that may get way worse before it subsides. Do we really want the map to be screaming bright red? Red is a very emotive colour. It has meaning. It can easily connotate danger, and death, which is still statistically extremely rare for coronavirus.

you cannot map totals using a choropleth thematic mapping technique. The reason is simple. Each of the areas on the map is a different size, and has a different number of people in it.

Learn how to write good emails, how to present your work, how to phrase your questions in a thoughtful manner.

I want to have a choice whether to forget or remember events, and I'd like to be able to potentially access forgotten ones.

Even ignoring quality of life you are looking at a 3-7 fold return on every minute you spend exercising in extended life,[1] perhaps even exceeding that if you are making optimal use of your time. Something just clicked and I was consistent since reading this. Even 1-fold return would worth it: basically you gain free consciousness (quality of thinking is shit when I exercise, but it's better than nothing).

Exobrain, or "second brain", or "brain dump" is something like public wiki where you can keep your notes, ideas and thoughts.

Annotation is the process of adding a layer of personal (with a potential for sharing) metadata on top of existing content such as highlights, notes, anchors etc.

Human brains seem to be best for generating new ideas. I want to learn more, think faster, distract less, interact and visualize, effortlessly remember everything; not memorize and do routine information processing, which computers seem better at.

Extended mind is the idea that your mind isn't limited by your physical body, but augmented by external means. Paper notes & diaries, data in your computer/phone/cloud – all these things contribute to your cognitive process, thinking and help you navigate the landscape of ideas. One of the biggest motivations to start dumping my brain out here, write and share is to offload my mind a bit and interact with people even in my physical absence.

I can't imagine going on a run without my HR monitor, because whatever the benefit exercise has and however exhausting run would be, at least I'll have a data point. learning about routine and trying to optimize routine is also way more fun than doing the actual routine Human body is fragile and needs constant care, but it's still a fascinating mechanism.

quantified self refers both to the cultural phenomenon of self-tracking with technology and to a community of users and makers of self-tracking tools who share an interest in “self-knowledge through numbers.”[1] Quantified Self practices overlap with the practice of lifelogging and other trends that incorporate technology and data acquisition into daily life, often with the goal of improving physical, mental, and/or emotional performance.

Its automated reasoning sounds great

In Grakn, these algorithms are built-in as native functionalities of the language.

code below instantiates a client, opens a session, and runs an insertion query

We will use the python client API to interact with Grakn.

We just created a Grakn keyspace experiment and defined its schema.

Now that we have the schema ready, the next step is to load it into Grakn.

docker exec -ti grakn bash -c '/grakn-core-all-linux/grakn console --keyspace experiment --file /grakn-core-all-linux/server/db/schema.gql'

Loading: /grakn-core-all-linux/server/db/schema.gql
...
{}
Successful commit: schema.gql

An attribute can be abstract if you never assign it directly and use it only as a parent type. Entities can be abstract, too, if they are never instantiated.

There's just one more step – defining the attribute types

name sub attribute,
    datatype string;

address sub attribute,
    datatype string;

timestamp sub attribute, abstract,
    datatype date;

    created sub timestamp;
    last-modified sub timestamp;
    last-accessed sub timestamp;
    penalty-until sub timestamp;

url sub attribute,
    datatype string;

Attributes can be assigned to anything, including relations.

We've ended up with three entities: user, badge and location. How to glue them together? Using relations.

location-of-user sub relation,
    relates located-user,
    relates user-location;

achievements sub relation,
    has score,
    relates contributor,
    relates award;

Some things are common to multiple users, like a location (e.g. Austin, TX, USA) or the types of badges they've been awarded (bronze, silver, gold). We'll model locations and badges as separate entities.

location sub entity,
    key address,
    plays user-location;

badge sub entity,
    key color,
    plays award;

Graql — Grakn's query language that allows you to model, query and reason over data.

What can we have in a schema? There are three types of things

schema – a skeleton structure that represents the logical view of the entire knowledge graph

To keep things nice and platform agnostic, let’s go with Docker.

Grakn is a knowledge base for intelligent systems. A quick look at their developer site and examples piqued my curiosity

Of the three primary color channels, red, green and blue, green contributes the most to luminosity.

Imagine that you're using a database to export them, so your schema is: TABLE Article(STRING id, STRING url, STRING title, DATETIME added). One day, the developers expose highlights (or annotations) from the private API and your export script stats receiving it in the response JSON. It's quite useful data to have! However, your database can't just magically change to conform to the new field.

Storage saved by using a database instead of plaintext is marginal and not worth the effort.

if necessary use databases as an intermediate layer to speed access up and as an additional interface to your data Nothing wrong with using databases for caching if you need it!

I want to argue very strongly against forcing the data in the database, unless it's really inevitable.

black and white with monotones

Basic Color Schemes

Warm colors exhibit energy and joy (best for personal messages), while cool colors convey calmness and peace (best for office use).

But I think we read a lot of self-help because we need to. As I’ve already mentioned, we need lots of examples to drive this wisdom home. We should be more forgiving of self-help (the genre) and more forgiving of ourselves. Putting wisdom into practice takes requires reading, reflection, and practice—but it’s worth it.

advice can either be arcane or obvious, general or specific.

no business book can predict what sorts of situations (businesses, market conditions, etc.) the reader will encounter, so instead it offers general, obvious-sounding rules.

We feel divinely inspired while reading Minimalism, but when it’s time to actually cull our wardrobes, it turns out we have good reasons for keeping everything!

We’re embarrassed by self-help because (at its best) it’s full of banal platitudes—but these are platitudes because they’re so general.

Wisdom Knowledge

So which is it? Is our obsession with self-help embarrassing or admirable? Is self-help snake oil or salvation? I’m going to argue that it’s both.

But what if you wanted wisdom, not knowledge? Are there books that contain wisdom? In other words, are there books that give you general-purpose, one-size-fits-all advice for navigating life? Of course there is! It’s called self-help.

“a wise person knows what to do in most situations, while a [knowledgeable]1 person knows what to do in situations where few others could.” In other words, wise people are moderately successful in many domains, while knowledgeable people are very successful in a few.

there are two sources of feeling like a noob: being stupid, and doing something novel. Our dislike of feeling like a noob is our brain telling us "Come on, come on, figure this out."

the more of a noob you are locally, the less of a noob you are globally.For example, if you stay in your home country, you'll feel less of a noob than if you move to Farawavia, where everything works differently. And yet you'll know more if you move. So the feeling of being a noob is inversely correlated with actual ignorance.

n the end, it didn’t matter if the students walked more than even 15,000 steps; they still gained weight

Scientists at EPFL in Switzerland have shown that you are more likely to initiate a voluntary decision as you exhale.

A combinaison of split(), subString(), removePrefix(), removeSuffix() is usually enough.

When you get tired of thinking about a piece of work and feeling bad for not finishing it yet, go "screw it, let's do it" and start with something, anything.

When you know that you don't have to make the greatest thing ever right from the start, it's easier to start. And then it's easier to continue.

Level 0 is no automation whatsoever. Level 1 is partial assistance with certain aspects of driving, like lane keep assist or adaptive cruise control. Level 2 is a step up to systems that can take control of the vehicle in certain situations, like Tesla's Autopilot or Cadillac's Super Cruise, while still requiring the driver to pay attention. Get past that and we enter the realm of speculation: Level 3 promises full computer control under defined conditions during a journey, Level 4 expands that to start-to-finish autonomous tech limited only by virtual safeguards like a geofence, and Level 5 is the total hands-off, go-anywhere-at-the-push-of-a-button experience.

The CEO of Volkswagen's autonomous driving division recently admitted that Level 5 autonomy—that's full computer control of the vehicle with zero limitations—might actually never happen.

Majority of the times, the only way to break into a circle is for someone within that circle to speak positively on your behalf.

I have observed something else under the sun. The fastest runner doesn’t always win the race, and the strongest warrior doesn’t always win the battle. The wise sometimes go hungry, and the skillful are not necessarily wealthy. And those who are educated don’t always lead successful lives. It is all decided by chance, by being in the right place at the right time. — Ecclesiastes 9:11

They simply possess the willpower and drive to observe people, get to know people, appear in gatherings that involve people that are aligned with their goals, and connect people with one another.

This quote from Richard Feynman is at the top of my blog’s landing page: I learned very early the difference between knowing the name of something and knowing something.

Summarizing a paper in your own words restructures the content to focus on learning rather than novelty.

Blogging has taught me how to read a paper because explaining something is a more active form of understanding. Now I summarize the main contribution in my own words, write out the notation and problem setup, define terms, and rederive the main equations or results. This process mimics the act of presenting and is great practice for it.

When I first started teaching myself to program, I felt that I had no imagination. I couldn’t be creative because I was too focused on finding the syntax bug or reasoning about program structure. However, with proficiency came creativity. Programming became less important than what I was building and why.

In my opinion the reason most people fail to do great research is that they are not willing to pay the price in self-development. Say some new field opens up that combines field XXX and field YYY. Researchers from each of these fields flock to the new field. My experience is that virtually none of the researchers in either field will systematically learn the other field in any sort of depth. The few who do put in this effort often achieve spectacular results.

Many of us have done this on exams, hoping for partial credit by stitching together the outline of a proof or using the right words in an essay with the hopes that the professor connects the dots for us.

Since water is denser than air, and the reflection is diffuse. A lot of light is internally reflected, thereof, increasing the probability of absorption at surface.

This is because the light now has a layer of water to go through. And due to the reflectance of water, not all light at the air-liquid-interface (border between air and water) goes through the water. Some of it is reflected.

There are two types of reflection (two ways the wave can be thrown back). Specular Diffuse

ericb 12 days ago | unvote [-] * Better googling. Time-restricted, url restricted, site restricted searches. Search with the variant parts of error messages removed.* Read the source of upstream dependencies. Fix or fork them if needed.* They're better at finding forks with solutions and gleaning hints from semi-related issues.* Formulate more creative hypothesis when obvious lines of investigation run out. The best don't give up.* Dig in to problems with more angles of investigation.* Have more tools in their toolbelt for debugging like adding logging, monkey-patching, swapping parts out, crippling areas to rule things out, binary search of affected code areas.* Consider the business.* Consider user-behavior.* Assume hostile users (security-wise).* Understand that the UI is not a security layer. Anything you can do with PostMan your backend should handle.* Whitelist style-security over blacklist style.* See eventual problems implied by various solutions.* "The Math."

technology diffused more easily along lines of latitude than along lines of longitude because climate changed more rapidly along lines of longitude making it more difficult for both humans and technologies to adapt

Anything that’s invented between when you’re fifteen and thirty-five is new and exciting and revolutionary and you can probably get a career in it.

"One of history’s few iron laws is that luxuries tend to become necessities and to spawn new obligations. Once people get used to a certain luxury, they take it for granted. Then they begin to count on it. Finally they reach a point where they can’t live without it.”

A 90s study showed that women preferred the scents of men whose immune systems were most different from their own immune-system genes. Evolutionarily this makes sense as, children should be healthier if their parents’ genes vary, protecting them from more pathogens.

Between 2011 and 2013, china used 50% more cement than the United States in the 20th century.Of the world’s 100 highest bridges, 81 are in China, including some unfinished ones.

Here’s Warren Buffett: “Cola has no taste memory. You can drink one at 9am, 11am, 5pm. You can't do that with cream soda, root beer, orange, grape. You get sick of them after a while. The average person drinks 64 ounces of liquid per day, and you can have all 64 ounces of that be Coke.”Same with Doritos, Cheetos, most popular junk food. They are engineered to overcome “sensory-specific satiety” and to give a sense of “vanishing caloric density.”

One of the tasks of true friendship is to listen compassionately and creatively to the hidden silences. Often secrets are not revealed in words, they lie concealed in the silence between words.

Video Games are a Booming IndustryThe video game industry generates more revenue than movies and music.

Humor treads at the frontier of consciousness. When a comic finds a funny joke, they are unearthing a truth that people are only kind of aware of, but the whole room grasps that everybody else is aware of the truth, and laughter ensues.

Highest Grossing Media Franchises

How the Sun Moves

“Twitter is the most amazing networking and learning network ever built.For someone whose pursuing their dream job, or chasing a group of mentors or peers, it’s remarkable. In any given field, 50-80% of the top experts in that field are on Twitter and they’re sharing ideas, and you can connect to them or follow them in your personal feed.If you get lucky enough and say something they find interesting, they might follow you, and the reason this becomes super interesting is that unlocks direct message, and now all of a sudden you can communicate directly or electronically with that individual. Very, very powerful.If you’re not using Twitter, you’re missing out.” — Bill Gurley

80% of Americans live, work, and hang out in the pink areas — 3.6 percent of the landmass of the lower 48 states.

"The easiest way to be discovered right now in technology and perhaps many fields is to create your own independent blog and write. There is a huge dearth in availability of good, current, first party content today.The single most important advice I can give to actually write is to write.The thing that happens which you don’t see until you write is that your content engages some of the smartest people who are lurking around the internet. And they reach out to you."

By some estimates, more than 50,000 pieces of artwork are stolen each year, amounting to annual losses of around $6 to $8 billion globally. This makes art theft one of the most valuable criminal enterprises around, exceeded only by drug trafficking and arms dealing.

Where is Wealth Concentrated?

This map shows the relative density of commercial shipping around the world. The darker the color, the busier the route.

I've noticed a weird pattern: In most of the best marriages I see, one person is an early-bird, and the other is a night-owl. They have opposite circadian rhythms.I think this is healthy. The two partners get the benefits of time together and time alone, which helps the marriage.

look around and figure out who you want to be on your team. Figure out the people around you that you want to work with for the rest of your life. Figure out the people who are smart & awesome, who share your values, who get things done — and maybe most important, who you like to be with and who you want to help win. And treat them right, always. Look for ways to help, to work together, to learn. Because in 20 years you’ll all be in amazing places doing amazing things.

It goes completely against what most believe, but out of all major energy sources, nuclear is the safest

Studies show it takes ~23 minutes to deeply refocus on something when you get disturbed

if you care at all about storing timestamps in MySQL, store them as integers and use the UNIX_TIMESTAMP() and FROM_UNIXTIME() functions.

The system clock is inaccurate. You're on a network? Every other system's clock is differently inaccurate.

A time format without an offset is useless.

If you want to store a humanly-readable time (e.g. logs), consider storing it along with Unix time, not instead of Unix time.

When storing a timestamp, store Unix time. It's a single number.

Most of your code shouldn't be dealing with timezones or local time, it should be passing Unix time around.

Unix time: Measured as the number of seconds since epoch (the beginning of 1970 in UTC). Unix time is not affected by time zones or daylight saving

GMT is still used: it's the British national timezone in winter. In summer it becomes BST.

Australian Eastern Standard Time is UTC+1000. e.g. 10:00 UTC is 20:00 EST on the same day.

GMT: UTC used to be called Greenwich Mean Time (GMT) because the Prime Meridian was (arbitrarily) chosen to pass through the Royal Observatory in Greenwich.

UTC: The time at zero degrees longitude (the Prime Meridian) is called Coordinated Universal Time (UTC is a compromise between the French and English initialisms)

we shield ourselves from existential threats, or consciously thinking about the idea that we are going to die, by shutting down predictions about the self,” researcher Avi Goldstein told The Guardian, “or categorizing the information as being about other people rather than ourselves.

test of whether they know how to look for help.Are they able to read a manual?Can they formulate a search query?How do they assess whether the tutorial they found is suitable or reliable?What steps do they take to make sure they're finding - and learning - the right information?

Zugzwang (German for "compulsion to move", pronounced [ˈtsuːktsvaŋ]) is a situation found in chess and other games wherein one player is put at a disadvantage because they must make a move when they would prefer to pass and not move

Today, my process is enjoyably unsophisticated. When I want to post something, I first write it in a text file, copy my last blog post’s HTML file, paste in my new article, make some slight adjustments, update my list of posts, add it to my RSS file, and that’s basically it. Any page on my website can be anything I want it to be, like how, for example, double clicking on this article leads to a small easter egg.

walking, cycling and more green spaces not only cut air pollution but also improved mental health.

“Although the studies included were from different parts of the world – eg China, the US, Germany – and varied in sample size, study design and measures of depression, the reported associations were very similar.”

The studies analysed took account of many factors that might affect mental health, including home location, income, education, smoking, employment and obesity. But they were not able to separate the potential impact of noise, which often occurs alongside air pollution and is known to have psychological effects.

more than 90% of the global population lives with air pollution above WHO-recommended levels

People exposed to an increase of 10 micrograms per cubic metre (µg/m3) in the level of PM2.5 for a year or more had a 10% higher risk of getting depression.

The data analysed in the new research linked depression with air pollution particles smaller than 2.5 micrometres (equivalent to 0.0025 millimetres and known as PM2.5)

Other research indicates that air pollution causes a “huge” reduction in intelligence and is linked to dementia. A comprehensive global review earlier in 2019 concluded that air pollution may be damaging every organ and virtually every cell in the human body.

the finest particulates from dirty air can reach the brain via both the bloodstream and the nose, and that air pollution has been implicated in increased [brain] inflammation, damage to nerve cells and to changes in stress hormone production, which have been linked to poor mental health,” Braithwaite said

“You could prevent about 15% of depression, assuming there is a causal relationship. It would be a very large impact, because depression is a very common disease and is increasing.” More than 264 million people have depression, according to the WHO.

Depression and suicide linked to air pollution in new global study Cutting toxic air might prevent millions of people getting depression, research suggests

Nothing truly novel, nothing that matters, is ever learned with ease

Leaders in every sector seem to agree: Learning is an imperative, not a cliché. Without it, careers derail and companies fail.

Unit Testing

End-to-End Testing

Integration Testing

There are three different methods of Automated Testing

The major selling point of Julia these days is in crafting differentiable algorithms (data-driven code that neural networks use in machine learning) in Flux (machine learning library for Julia)

I decided that the name of the game is to optimise quality of life. That means, infrequent brutal deadlines, minimal (pref. zero) commute, opportunity to learn, and spend time with family and friends and be of use to society at large.

My mom is the best example of how to enjoy life in the present. She takes her work seriously, but doesn't take herself too seriously, and by putting fun first, every accomplishment and accolade is merely a bonus

But we can take steps to control and lower our stress levels and, as a result, our arousal. Techniques like consciously controlling your breathing, and listening to chilled music have been known to help. More traditional advice, like reducing how much coffee you drink, eating a balanced diet and getting enough sleep each night should also be helpful

In our third study, we had 169 participants jog on the spot for 60 seconds. We found that these participants were more likely to share embarrassing stories – or open up to others – after physical exercise. Usually, people might disclose personal information like this to people that are close to them, but it seems we are more likely to open up to strangers when aroused, particularly by physical exercise

Information that we’re usually careful about disclosing, like secrets and very personal information, are more likely to be disclosed when we default to more automatic responses; mainly because they require some degree of effort to conceal.

At some point, we replaced the order of displaying the superpower packs (SP) from ascending to descending

Users don’t appreciate it when you try to trick them out of their money, or when they think you are doing that. A better approach would be to give them the opportunity to get what they want for free (even with a lot of work involved), and give an alternative purchase option. In this case the purchase will be perceived as a small cheat to make life easier instead of a shady scheme to get users to pay

There were four packs respectively containing 25, 50, 150 and 500 superpowers. We increased the biggest power pack from 500 to infinity. Practically, nothing changed. 500 superpowers were more than enough for the entire game, and very few users had spent all of it. However, after the change was made, the revenue from this pack grew by 50%

I observed a similar effect in my own business when I was producing and selling metal license plates (sold via partner brick-and-mortar stores and through our own online store). At the start, the prices we set were relatively low ($3-5). But in a few months, we raised the prices by 2-3 times, and the plates then cost $15-25. Contrary to our expectations, the conversion rate almost doubled, as well as the average order amount.

With a vitamin C priced at $3, 100% of participants experienced relief. But the drug priced at $0.1 only worked in 50% of cases

The word “free” makes any product more attractive to its potential customers. If you have a way to distribute your product for free, at least partially (a trial option, a limited version), then make sure to use it. This approach will greatly expand the top of your funnel. Once done, you will simply have to learn how to convert these new users into the paying ones

I decided to compare how those who got it for free and those paid for it went through the levels in the game. There was a hypothesis that those who got it for “free” should stop using the game faster and sooner than those who paid for it. The hypothesis turned out to be wrong. The users of both the free and the paid version had identical behavior in the first 40 levels However, after level 40, the “free” players started quitting the game much faster. I interpreted this as those who received the game for free appreciated it less, so their motivation to go till the end or return to it after a couple of days was less

When we make decisions, our perception is influenced by a lot of factors such as presentation, packaging, brand, opinions of people around us, experts’ opinions, our own expectations, etc. Each of these factors can ultimately determine how much a person will like your product and how much she will be willing to pay for it

In one case, the participants were given brochures describing the capabilities of a new audio system. The only difference between the brochures was that the first one was published on behalf of the system’s manufacturer and the second one on behalf of an independent research center. The participants who had seen the second brochure were willing to pay twice as much as the first group for the audio system

those who received coffee when the table was beautifully set appreciated the taste way more, and were also ready to pay more for it

Joshua Bell, one of the best concert violinists in the world played for free, for 45 minutes, on a violin worth $3.5 million dollars at a subway station. He managed to raise $32. Most people (98%) who passed by paid no attention to him, only 2% gave him some money, and less than 0.5% stopped to listen (those were the people who actually recognized him)

If you want to change the rules of the game in a field that you are about to enter, try to portray your product as something new and different. Doing so will enable you to set the rules of the game from scratch and be the first one to establish the anchor. And when you install the anchor, do not lower the price; there will still be time for that (making a discount always sounds better than raising the price)

When the sales agents of a health insurance company that was selling its services via phone asked people (who agreed to proceed) why they chose their company, the proportion of those who eventually decided to purchase the insurance increased significantly. As they thought about the answer to this question, the respondents subconsciously convinced themselves that they had made the right choice, further strengthening their decision and eventually leading to their making the purchase

People also tend to form new “rules” when they encounter something for the first time. Starbucks is very different from other coffee stores. Therefore, when interacting with them, people create new rules instead of resorting to existing patterns

we tend to base our decisions on things we’ve experienced before, to make decisions easier

It is difficult to find a logical explanation for this, but apparently the prices that end with 9 trigger some kind of automatic mechanism

Offering to proceed with a $1 per day tariff and the one that costs $350 per year are mathematically equivalent, but trigger different reactions in customers. The first option can be compared to purchasing a water bottle in a grocery store, and the second option is more like purchasing a mobile phone

Mathematically equivalent statements are not necessarily equivalent psychologically

Do not lower prices. The price that you declare at the very beginning will become the reference point. You can also try to show your customers big numbers before starting to talk about the money

people are guided by the available prices to assess the rest of the offered goods

Salesmen in retail stores try to sell the most expensive things first, or at least offer them to customers. For instance, a person who came to buy a suit is first shown the suits. When the customer makes his choice, then the salesperson suggests appropriate accessories, such as a tie to go with the suit. Compared to the suit’s price, the tie looks very inexpensive and is an easy upsell

We rarely think in absolute terms, and we don’t have a universal measure to understand the value of a certain thing. Therefore, we tend to evaluate things by comparing them to others

The lack of a ready-made pattern of behavior makes people rely on “simple” factors in decision-making (such as other people’s behavior, template principles, pre-designed baits, etc.), rather than the correct ones

The circles drawn in the center of the image above are identical. But depending on their environment, their perceived size changes

New study shows that our personal memories might not be personal at all. All it takes to change your memories is thinking about a different person, and considering how they would approach what happened to you. Perhaps our character isn’t as unique as we think, but more fluid, and changed by every person we meet. Our evaluation of ourselves changes even when we think of objects, not just other people

if your goal is to build a remarkable life, then busyness and exhaustion should be your enemy

Hard work is deliberate practice. It’s not fun while you’re doing it, but you don’t have to do too much of it in any one day (the elite players spent, on average, 3.5 hours per day engaged in deliberate practice, broken into two sessions). It also provides you measurable progress in a skill, which generates a strong sense of contentment and motivation

The elite players were spending almost three times more hours than the average players on deliberate practice

The average players, they discovered, spread their work throughout the day. A graph included in the paper, which shows the average time spent working versus the waking hours of the day, is essentially flat. The elite players, by contrast, consolidated their work into two well-defined periods

the elite players slept an hour more per night than the average players

the elite players were significantly more relaxed than the average players, and the best of the best were the most relaxed of all

the more files you have and the bigger your project, the more resources VS Code will start to consume. The Search Indexing and File Watcher scripts start eating up your memory. Moreover, to work on such a project, you will open each file in a new tab, leading to multiple VS Code instances running simultaneously, and eventually, your CPU usage will start to look like this

FKs don't work well with online schema migrations.

FKs are a performance impact. The fact they require indexes is likely fine, since those indexes are needed anyhow. But the lookup made for each insert/delete is an overhead.

To grow, trees photosynthesize and turn water and carbon dioxide (pulled from the air), into hydrocarbons. A living tree sucks carbon dioxide from the air and locks it into wood as it grows. Even when the tree dies (unless we burn it), the carbon is still locked up in the wood

For a wood fire, ash is primarily composed of metal carbonates and oxides (such as Calcium Carbonate, and Potassium Carbonate), from the compounds in the original wood

As long as there is a source of fuel (and oxygen), the fire will burn

As the fire gets hotter, more complete combustion occurs, less smoke is produced, and the flames lose the yellow color, turning more blue

yellow flames seen in a fire are the result of incomplete combustion

smoke produced (early stages of fire) is unburned carbon

It is the volatile compounds that out-gas from the wood, and eagerly react with oxygen, that are burning, and generate the flames we see

When the temperature of wood is increased (through application of heat), first the water is driven off. This occurs up to about 200°C. Between approximately 200°C–280°C the heat starts to break down the hemicellulose compounds into Carbon Monoxide, Carbon Dioxide, Acetic Acid, (and more water vapour); these are driven out. Between 280°–500° decomposition of the longer cellulose and lignin begins and produces light tars and Methyl Alcohol

A couple of hundred intermediate products (organic acids, ketones, esters, aldehydes …) have been identified as being produced by the pyrolysis of wood

The pyrolysis of wood is an incredibly intricate and complex process that is not completely mapped out and the exact output depends of many variables

The correct term to describe what is going on when we ‘burn’ wood is Pyrolysis

The chemical composition of wood varies from species to species, but is approximately 50% carbon, 42% Oxygen, 6% Hydrogen, 1% Nitrogen, and 1% other elements (mainly Calcium, Potassium, Sodium, Magnesium, Iron, and Manganese) by weight

Wood is the hard-fibrous material that comes from the trunk, stems, roots, and branches of a once living tree