Build a function that takes a list of strings as input, returns a boolean indicating whether all the strings containing a word

plizak asure 0
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I am write a function that can return Boolean if every string in a list contains the word 'red'. Below is the code that I came up with, it worked well for test case AllRed(["red hat", "a pair of red shoes", "three red apples"]); and test case AllRed(["red hat", "white shirt", "black eyes"]). However, when I tested it with an empty list, it returned True.

def AllRed  (lst):
 return all("red" in i for i in lst)
AllRed([])

It is supposed to return false for empty list.

string function list python
2 Answers

The all() function is required to return True for empty lists. This ensures that the following equivalence will always be true:

all(list1) and all(list2) == all(list1 + list2)

When list1 is empty, list1+list2 is the same as list2. So we need all(list1) to return True.

Similarly, any() returns False for an empty list, so that

any(list1) or any(list2) == any(list1 + list2)

is true.

Barmar0

It is because when your iterable (lst) is empty, there is nothing to iterate over; and if you see how all() works, it returns True when iterable is empty.

See how all() works

anandnpr0
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