query: Why is undefined == undefined but NaN != NaN?
positive_passages.docid: 83165
positive_passages.text: What is the rationale for all comparisons returning false for IEEE754 NaN values?
negative_passages.docid: 49446
negative_passages.text: How to check for an undefined or null variable in JavaScript?
negative_passages.docid: 151825
negative_passages.text: Is there any difference between "foo is None" and "foo == None"?
negative_passages.docid: 92587
negative_passages.text: Surprised that global variable has undefined value in JavaScript
negative_passages.docid: 153624
negative_passages.text: What's the difference between is_null($var) and ($var === null)?
negative_passages.docid: 23730
negative_passages.text: Why is 'True == not False' a syntax error in Python?
negative_passages.docid: 158810
negative_passages.text: Why does >= return false when == returns true for null values?
negative_passages.docid: 3941
negative_passages.text: What's the difference between ".equals" and "=="?
negative_passages.docid: 151096
negative_passages.text: Why does the expression 0 < 0 == 0 return False in Python?
negative_passages.docid: 79050
negative_passages.text: Python ( or general programming ). Why use  instead of != and are there risks?
negative_passages.docid: 80488
negative_passages.text: Explanation of method for showing that $\frac{0}{0}$ is undefined
negative_passages.docid: 3526
negative_passages.text: How to determine equality for two JavaScript objects?
negative_passages.docid: 144960
negative_passages.text: Why is Javascript's "in" operator consistently slower than strict member comparison to undefined?
negative_passages.docid: 133999
negative_passages.text: Does variables' order matter when doing == and === comparisons?
negative_passages.docid: 69801
negative_passages.text: What does it mean when ST_Equals returns false and `=` returns true?
negative_passages.docid: 150558
negative_passages.text: Lua operators, why isn't +=, -= and so on defined?
negative_passages.docid: 39485
negative_passages.text: Why does ('0' ? 'a' : 'b') behave different than ('0' == true ? 'a' : 'b')