&& and and are alternate tokens and are functionally same, from section 2.6 Alternative tokens from the C++ draft standard: Alternative Primary and && Is one of the entries in the Table 2 – Alternative tokens and it says in subsection 2: In all respects of the language, each alternative token behaves the same, respectively, … Read more
The corresponding operator is |: df[(df < 3) | (df == 5)] would elementwise check if value is less than 3 or equal to 5. If you need a function to do this, we have np.logical_or. For two conditions, you can use df[np.logical_or(df<3, df==5)] Or, for multiple conditions use the logical_or.reduce, df[np.logical_or.reduce([df<3, df==5])] Since the … Read more
All design processes result in compromises between mutually incompatible goals. Unfortunately, the design process for the overloaded && operator in C++ produced a confusing end result: that the very feature you want from && — its short-circuiting behavior — is omitted. The details of how that design process ended up in this unfortunate place, those … Read more
The != operator serves this purpose for bool values.
From the help page for Logical Operators, accessible by ?”&&”: & and && indicate logical AND and | and || indicate logical OR. The shorter form performs elementwise comparisons in much the same way as arithmetic operators. The longer form evaluates left to right examining only the first element of each vector. Evaluation proceeds only … Read more
Updated answer: Apologies, I missed the word “logical” in your question even though it is there. (I’ve taken the liberty of emphasizing it a bit with an edit.) Consider the case where you want any side-effects to always occur, regardless of whether the left-hand expression evaluates true or false. E.g., contrast: if (foo() & bar()) … Read more
Yes. In C# && and || are short-circuiting and thus evaluates the right side only if the left side doesn’t already determine the result. The operators & and | on the other hand don’t short-circuit and always evaluate both sides. The spec says: The && and || operators are called the conditional logical operators. They … Read more
&& operator: If the left operand and the right operand are both different than 0 it evaluates to 1 otherwise it evaluates to 0. If the left operand is 0, the right operand is not evaluated and the result is 0. 0x65 && 0x55 is evaluated to 1.
The correct operator is %in% here. Here is an example with dummy data: set.seed(1) dat <- data.frame(bf11 = sample(4, 10, replace = TRUE), foo = runif(10)) giving: > head(dat) bf11 foo 1 2 0.2059746 2 2 0.1765568 3 3 0.6870228 4 4 0.3841037 5 1 0.7698414 6 4 0.4976992 The subset of dat where bf11 … Read more
To quote from ?Logic: NA is a valid logical object. Where a component of x or y is NA, the result will be NA if the outcome is ambiguous. In other words NA & TRUE evaluates to NA, but NA & FALSE evaluates to FALSE. See the examples below. The key there is the word … Read more