boolean-operations - w3toppers.com

Difference between Boolean operators && and & and between || and | in R

How to calculate boolean expression in Spirit

Here goes a quick and dirty demo based on my old Boolean Parser answer. This is a visitor that evaluates the AST you pass it: struct eval : boost::static_visitor<bool> { eval() {} // bool operator()(const var& v) const { if (v==”T” || v==”t” || v==”true” || v==”True”) return true; else if (v==”F” || v==”f” || … Read more

Why doesn’t c++ have &&= or ||= for booleans?

A bool may only be true or false in C++. As such, using &= and |= is relatively safe (even though I don’t particularly like the notation). True, they will perform bit operations rather than logical operations (and thus they won’t short-circuit) but these bit operations follow a well-defined mapping, which is effectively equivalent to … Read more

Inverting a numpy boolean array using ~

short answer: YES Ref: http://docs.scipy.org/doc/numpy/reference/generated/numpy.invert.html Notice: Computes the bit-wise NOT of the underlying binary representation of the integers in the input arrays. This ufunc implements the C/Python operator ~. and bitwise_not is an alias for invert: >> np.bitwise_not is np.invert >> True

Element-wise logical OR in Pandas

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

Using “and” and “or” operator with Python strings [duplicate]

Suppose you are using the value of parameter, but if the value is say None, then you would rather like to have an empty string “” instead of None. What would you do in general? if parameter: # use parameter (well your expression using `” ” + parameter` in this case else: # use “” … Read more

De Morgan’s rules explained

Overview of boolean algebra We have two values: T and F. We can combine these values in three ways: NOT, AND, and OR. NOT NOT is the simplest: NOT T = F NOT F = T We can write this as a truth table: when given.. | results in… ============================ T | F F | … Read more

Boolean operators vs Bitwise operators

Here are a couple of guidelines: Boolean operators are usually used on boolean values but bitwise operators are usually used on integer values. Boolean operators are short-circuiting but bitwise operators are not short-circuiting. The short-circuiting behaviour is useful in expressions like this: if x is not None and x.foo == 42: # … This would … Read more

Boolean operators && and ||

The shorter ones are vectorized, meaning they can return a vector, like this: ((-2:2) >= 0) & ((-2:2) <= 0) # [1] FALSE FALSE TRUE FALSE FALSE The longer form evaluates left to right examining only the first element of each vector, so the above gives ((-2:2) >= 0) && ((-2:2) <= 0) # [1] … Read more