python - How to check if lowercase letters exist? -

i have been observing unusual behavior .islower() , .isupper() methods in python. example:

>>> test = '8765iouy9987oiuy' >>> test.islower() false >>> test.isupper() false 

however, following mixed string value seems work:

>>> test2 = 'b1' >>> test2.islower() true >>> test2.isupper() false 

i not understand anomaly. how can detect lower case letters in test?

islower() , isupper() return true if all letters in string lowercase or uppercase, respectively.

you'd have test individual characters; any() , generator expression makes relatively efficient:

>>> test = '8765iouy9987oiuy' >>> any(c.islower() c in test) true >>> any(c.isupper() c in test) true