Exchange type Default pre-declared names Direct exchange (Empty string) and amq.direct Fanout exchange amq.fanout Topic exchange amq.topic Headers exchange amq.match (and amq.headers in RabbitMQ)

Write an interpreter that handles arithmetic expressions like “7 - 3 + 2 - 1” from scratch. Use any programming language you’re comfortable with and write it off the top of your head without looking at the examples. When you do that, think about components involved: a lexer that takes an input and converts it into a stream of tokens, a parser that feeds off the stream of the tokens provided by the lexer and tries to recognize a structure in that stream, and an interpreter that generates results after the parser has successfully parsed (recognized) a valid arithmetic expression. String those pieces together. Spend some time translating the knowledge you’ve acquired into a working interpreter for arithmetic expressions

isdigit():

However, you can also give map multiple collections. Here’s a simple example to show how this works: