erl notes

gistfile1.txt

variables begin with an uppercase letter.
you can assign a value to a variable exactly once
The = operator (not the variables) has the role of comparing values and complaining if they're different. If they're the same, it returns the value:

If you're testing in the shell and save the wrong value to a variable, it is possible to 'erase' that variable by using the function f(Variable).. If you wish to clear all variable names, do f()..

Erlang won't care about floats and integers in arithmetic, but will do so when comparing them
6> 5 =:= 5.
true
7> 1 =:= 0.
false
8> 1 =/= 0.
true
9> 5 =:= 5.0.
false
10> 5 == 5.0.
true
11> 5 /= 5.0.
false


he correct ordering of each element in a comparison is the following:
number < atom < reference < fun < port < pid < tuple < list < bit string

tuple {v1,v2,v3, ...}

Erlang will print lists of numbers as numbers only when at least one of them could not also represent a letter! There is no such thing as a real string in Erlang!

1> [2*N || N <- [1,2,3,4]].
[2,4,6,8]

2> [X || X <- [1,2,3,4,5,6,7,8,9,10], X rem 2 =:= 0].
[2,4,6,8,10]

NewList = [Expression || Pattern <- List, Condition1, Condition2, ... ConditionN]
NewList = [Expression || GeneratorExp1, GeneratorExp2, ..., GeneratorExpN, Condition1, Condition2, ... ConditionM].