Pythonic way of checking if a condition holds for any element of a list

Python has a built in any() function for exactly this purpose.

any():

if any(t < 0 for t in x):
    # do something

Also, if you're going to use "True in ...", make it a generator expression so it doesn't take O(n) memory:

if True in (t < 0 for t in x):

Use any().

if any(t < 0 for t in x):
    # do something