Check if a predicate evaluates true for all elements in an iterable in Python
PythonPython Problem Overview
I am pretty sure there is a common idiom, but I couldn't find it with Google Search...
Here is what I want to do (in Java):
// Applies the predicate to all elements of the iterable, and returns
// true if all evaluated to true, otherwise false
boolean allTrue = Iterables.all(someIterable, somePredicate);
How is this done "Pythonic" in Python?
Also would be great if I can get answer for this as well:
// Returns true if any of the elements return true for the predicate
boolean anyTrue = Iterables.any(someIterable, somePredicate);
Python Solutions
Solution 1 - Python
Do you mean something like:
allTrue = all(somePredicate(elem) for elem in someIterable)
anyTrue = any(somePredicate(elem) for elem in someIterable)
Solution 2 - Python
allTrue = all(map(predicate, iterable))
anyTrue = any(map(predicate, iterable))
Solution 3 - Python
Here is an example that checks if a list contains all zeros:
x = [0, 0, 0]
all(map(lambda v: v==0, x))
# Evaluates to True
x = [0, 1, 0]
all(map(lambda v: v==0, x))
# Evaluates to False
Alternative you can also do:
all(v == 0 for v in x)
Solution 4 - Python
You can use 'all' and 'any' builtin functions in Python:
all(map(somePredicate, somIterable))
Here somePredicate is a function and all will check if bool() of that element is True.