PHP loose comparison with ==
1736
How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators differ?
9173
What are the PHP operators "?" and ":" called and what do they do?
32886
What is the difference between != and =! in Java?
60338
Null vs. False vs. 0 in PHP
36929
Why does comparing strings using either '==' or 'is' sometimes produce a different result?
152804
Double? Integer? -- PHP
25703
Best way to test for a variable's existence in PHP; isset() is clearly broken
69801
What does it mean when ST_Equals returns false and `=` returns true?
10283
Compare two version strings in PHP
89873
PHP: a short cut for isset and !empty?
17498
PHP parse/syntax errors; and how to solve them
37909
Understanding nested PHP ternary operator
49486
Problem with $_POST, if isset() and mysql_fetch_assoc(): echo returns correct value, page source always returns else value
60222
Weird PHP floating point behavior
139204
Why do numeric string comparisons give unexpected results?
4772
Difference between "not equal" operators  and != in PHP
89993
comparing arrays in php, without caring for the order