How good is startswith?

Question

Is

text.startswith(\'a\')  

better than

text[0]==\'a\'  

?

Knowing text is not empty and we a

Answer 1

def compo2():
    n = "abba"
    for i in range(1000000):
        n[:1]=="_"

is faster than

def compo():
    n = "abba"
    for i in range(1000000):
        n.startswith("_")

cProfile reports 0.061 for compo2 compared to 0.954 for compo on my machine. This of interest in case you want to make a LOT of prefix checks for various "_mystring". If most strings don't start with underscores then using string[:1]== char before using startswith is an option to optimize your code. In a real application this method saved me about 15% of cpu time.