efficiently checking that string consists of one character in Python

Question

What is an efficient way to check that a string s in Python consists of just one character, say \'A\'? Something like all_equal(s, \'A\')

Answer 1

Try using the built-in function all:

all(c == 'A' for c in s)

Answer 2

Adding another solution to this problem

>>> not "AAAAAA".translate(None,"A")
True