有没有办法判断一个字符串切片是否在 Python 中的另一个字符串中？

Question

I am working on a larger project but I've arrived at an issue where I am taking a slice from a string and I am attempting to tell if the slice is in a main string. The problem is that even though the types are the same it seems that the 'in' operator and 'index' operators don't work with the slice. Is there a way to tell if a slice is contained in a 'main string' or can you not compare slices and strings in that way? Here is some example code on what I am trying to accomplish:

x = ['dog']
value = 'dog'
y = 'All values with: ' + value
searchvalue = y[16:]
for i in x:
    if searchvalue in i:
        print('Is in')
    else:
        print('Not in')

So I want to be able to tell that the value 'dog' taken as a slice from 'y' is in 'x'. I fee like it should be simple but I've come to a dead end so far.

Answer 1

You should really consider using regex :

import re                                                                                                                                                                                                  
foo = 'some random string'                                                                                                                                                                                 
found = re.match(foo[:3], foo)

It will return None if not found.

Answer 2

You are trying to find dog instead of dog Change searchvalue to this

searchvalue = y[17:]

Answer 3

The problem in your code is the index number. Use 17 or searchvalue.strip()