Python Language Tutorial => First truthy/falsy element of a...

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Example

# First falsy element or last element if all are truthy:
reduce(lambda i, j: i and j, [100, [], 20, 10])    # = []
reduce(lambda i, j: i and j, [100, 50, 20, 10])    # = 10

# First truthy element or last element if all falsy:
reduce(lambda i, j: i or j, [100, [], 20, 0])     # = 100
reduce(lambda i, j: i or j, ['', {}, [], None])   # = None

Instead of creating a lambda-function it is generally recommended to create a named function:

def do_or(i, j):
    return i or j

def do_and(i, j):
    return i and j

reduce(do_or, [100, [], 20, 0])                   # = 100
reduce(do_and, [100, [], 20, 0])                  # = []

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