According to the help file ?`==` : If the two arguments are atomic vectors of different types, one is coerced to the type of the other, the (decreasing) order of precedence being character, complex, numeric, integer, logical and raw. So TRUE is coerced to “TRUE” (i. e. as.character(TRUE)), hence the equality. The equivalent of an … Read more
Think of ! (negation operator) as “not”, || (boolean-or operator) as “or” and && (boolean-and operator) as “and”. See Operators and Operator Precedence. Thus: if(!(a || b)) { // means neither a nor b } However, using De Morgan’s Law, it could be written as: if(!a && !b) { // is not a and is … Read more
To invert a boolean Series, use ~s: In [7]: s = pd.Series([True, True, False, True]) In [8]: ~s Out[8]: 0 False 1 False 2 True 3 False dtype: bool Using Python2.7, NumPy 1.8.0, Pandas 0.13.1: In [119]: s = pd.Series([True, True, False, True]*10000) In [10]: %timeit np.invert(s) 10000 loops, best of 3: 91.8 µs per … Read more
Order of operations causes (0 < 5 < 3) to be interpreted in javascript as ((0 < 5) < 3) which produces (true < 3) and true is counted as 1, causing it to return true. This is also why (0 < 5 < 1) returns false, (0 < 5) returns true, which is interpreted … Read more
As you can see, the AND operator drops every row in which at least one value equals -1. On the other hand, the OR operator requires both values to be equal to -1 to drop them. That’s right. Remember that you’re writing the condition in terms of what you want to keep, not in terms … Read more
Those are the bitwise AND and bitwise OR operators. int a = 6; // 110 int b = 4; // 100 // Bitwise AND int c = a & b; // 110 // & 100 // —– // 100 // Bitwise OR int d = a | b; // 110 // | 100 // —– … Read more
The statement (4 > y > 1) is parsed as this: ((4 > y) > 1) The comparison operators < and > evaluate left-to-right. The 4 > y returns either 0 or 1 depending on if it’s true or not. Then the result is compared to 1. In this case, since 0 or 1 is … Read more
Since nobody has broached the subject of why these are useful: I use bitwise operations a lot when working with flags. For example, if you want to pass a series of flags to an operation (say, File.Open(), with Read mode and Write mode both enabled), you could pass them as a single value. This is … Read more
Yep, both and and or operators short-circuit — see the docs.
You misunderstand how boolean expressions work; they don’t work like an English sentence and guess that you are talking about the same comparison for all names here. You are looking for: if x == 1 or y == 1 or z == 1: x and y are otherwise evaluated on their own (False if 0, … Read more