CODEWITHSUNDEEP
pythondebugging
user2284926
user2284926

Reputation: 651

Check if a particular string appears in another string

I am practicing my python coding on this website. This is the problem

Return True if the given string contains an appearance of "xyz" where the xyz is 
not directly preceeded by a period (.). So "xxyz" counts but "x.xyz" does not. 

xyz_there('abcxyz') → True
xyz_there('abc.xyz') → False
xyz_there('xyz.abc') → True

This is my code , for some unknown reason , i dont pass all the testcases. I have problems debugging it

def xyz_there(str):

    counter = str.count(".xyz")
    if ( counter > 0 ):
        return False
    else:
        return True

Upvotes: 1

Views: 1206

Answers (2)

Jon Clements
Jon Clements

Reputation: 142136

It appears the website doesn't allow import, so the simplest is probably:

'xyz' in test.replace('.xyz', '')

Otherwise, you can use a regular expression with a negative look behind assertion:

import re

tests = ['abcxyz', 'abc.xyz', 'xyz.abc']
for test in tests:
    res = re.search(r'(?<!\.)xyz', test)
    print test, bool(res)

#abcxyz True
#abc.xyz False
#xyz.abc True

Upvotes: 4

DSM
DSM

Reputation: 353019

One way to see if there's an xyz which isn't part of .xyz is to count the number of xyzs, count the number of .xyzs, and then see if there are more of the first than the second. For example:

def xyz_there(s):
    return s.count("xyz") > s.count(".xyz")

which passes all the tests on the website.

Upvotes: 3

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