” == ‘0’ // false The left hand side is an empty string, and the right hand side is a string with one character. They are false because it is making a comparison between two un identical strings (thanks Niall). 0 == ” // true Hence, why this one is true, because 0 is falsy … Read more
Yes. Any operators classified as comparisons can be chained. From the language reference: Formally, if a, b, c, …, y, z are expressions and op1, op2, …, opN are comparison operators, then a op1 b op2 c … y opN z is equivalent to a op1 b and b op2 c and … y opN … Read more
From the SymPy documentation == represents exact structural equality testing. “Exact” here means that two expressions will compare equal with == only if they are exactly equal structurally. Here, (x+1)^2 and x^2+2x+1 are not the same symbolically. One is the power of an addition of two terms, and the other is the addition of three … Read more
In C++, structs do not have a comparison operator generated by default. You need to write your own: bool operator==(const MyStruct1& lhs, const MyStruct1& rhs) { return /* your comparison code goes here */ }
All iterators are equality comparable. Only random access iterators are relationally comparable. Input iterators, forward iterators, and bidirectional iterators are not relationally comparable. Thus, the comparison using != is more generic and flexible than the comparison using <. There are different categories of iterators because not all ranges of elements have the same access properties. … Read more
1 == 1 == 2 // this true == 2 // becomes this 1 == 2 // which becomes this, and is false 2 > 1 == 1 // this true == 1 // becomes this 1 == 1 // which becomes this, and is true …and so on. If you’re wondering about the conversion, … Read more
I’d like to do it all by myself.. You should only compare the values of Obj::field2 if the values of Obj::field1 are equal. The easy-to-understand way: /* This will meet the requirements of Strict-Weak-Ordering */ if (a.field1 != b.field1) return a.field1 < b.field1; else return a.field2 < b.field2; The correct (recommended) way: The “correct” way … Read more
It has to do with operator precedence in Python (the interpreter thinks you’re comparing True to not, since == has a higher precedence than not). You need some parentheses to clarify the order of operations: True == (not False) In general, you can’t use not on the right side of a comparison without parentheses. However, … Read more
$a === $b (Identical) TRUE if $a is equal to $b, and they are of the same type. (introduced in PHP 4) PHP Docs
The equality operator will attempt to make the data types the same before making the comparison. On the other hand, the identity operator requires both data types to be the same as a prerequisite. There are quite a few other posts out there similar to this questions. See: How do the PHP equality (== double … Read more