Then I gave the question a longer, more descriptive title: I made it an actual question (with a question mark and everything), and replaced the term "lazy evaluation" with a more concrete description. The goal is to make the question more recognizable and more searchable. Hopefully this way, people who need this information have a better chance of finding it with a search engine; people who click through to it from a search page (either on Stack Overflow or from external search) will take less time to verify that it's the question they're trying to answer; and other curators will be able to close duplicates more quickly and more accurately. This edit also improves visibility for some related questions (and I made similar changes elsewhere to promote this one appropriately).

Hard disagree - they weren't nobodies, Naspers was already a media juggernaut by 2001 (print and TV).

cant you see he has only 11 reputations, and how can he comment?

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Overall, there's a strong correlation between job satisfaction and pushing code into production. 65% of developers who never check in code are satisfied at their jobs vs. 77% satisfaction rate among developers who commit code multiple times per day. Developers want to code! (Or maybe happy developers just commit more than everyone else.)

R Grouping functions: sapply vs. lapply vs. apply. vs. tapply vs. by vs. aggregate var ados = ados || {}; ados.run = ados.run || []; ados.run.push(function () { ados_add_placement(22,8277,"adzerk794974851",4).setZone(43); }); up vote 463 down vote favorite 606 Whenever I want to do something "map"py in R, I usually try to use a function in the apply family. (Side question: I still haven't learned plyr or reshape -- would plyr or reshape replace all of these entirely?) However, I've never quite understood the differences between them [how {sapply, lapply, etc.} apply the function to the input/grouped input, what the output will look like, or even what the input can be], so I often just go through them all until I get what I want. Can someone explain how to use which one when? [My current (probably incorrect/incomplete) understanding is... sapply(vec, f): input is a vector. output is a vector/matrix, where element i is f(vec[i]) [giving you a matrix if f has a multi-element output] lapply(vec, f): same as sapply, but output is a list? apply(matrix, 1/2, f): input is a matrix. output is a vector, where element i is f(row/col i of the matrix) tapply(vector, grouping, f): output is a matrix/array, where an element in the matrix/array is the value of f at a grouping g of the vector, and g gets pushed to the row/col names by(dataframe, grouping, f): let g be a grouping. apply f to each column of the group/dataframe. pretty print the grouping and the value of f at each column. aggregate(matrix, grouping, f): similar to by, but instead of pretty printing the output, aggregate sticks everything into a dataframe.] r sapply tapply r-faq