Python - Check If string Is In bigger String

Question

I'm working with Python v2.7, and I'm trying to find out if you can tell if a word is in a string.

If for example i have a string and the word i want to find:

str = "ask and asked, ask are different ask. ask"
word = "ask"

How should i code so that i know that the result i obtain doesn't include words that are part of other words. In the example above i want all the "ask" except the one "asked".

I have tried with the following code but it doesn't work:

def exact_Match(str1, word):
    match = re.findall(r"\\b" + word + "\\b",str1, re.I)
    if len(match) > 0:
        return True
    return False

Can someone please explain how can i do it?

What Casimir is basically saying is either use r"\b" or use "\\b". In your snippet, the correct call would thus be either r"\b" + word + r"\b" or "\\b" + word + "\\b" — Jerry
– Jerry, Commented Apr 28, 2015 at 11:54

Kasravnd · Accepted Answer · 2015-04-28 12:10:50Z

3

You can use the following function :

>>> test_str = "ask and asked, ask are different ask. ask"
>>> word = "ask"

>>> def finder(s,w):
...   return re.findall(r'\b{}\b'.format(w),s,re.U)
... 
>>> finder(text_str,word)
['ask', 'ask', 'ask', 'ask']

Note that you need \b for boundary regex!

Or you can use the following function to return the indices of words : in splitted string :

>>> def finder(s,w):
...   return [i for i,j in enumerate(re.findall(r'\b\w+\b',s,re.U)) if j==w]
... 
>>> finder(test_str,word)
[0, 3, 6, 7]

edited Apr 28, 2015 at 12:10

answered Apr 28, 2015 at 11:31

Kasravnd

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4 Comments

Kasravnd Over a year ago

@FranciscoF read complete doc in docs.python.org/3/library/stdtypes.html#str.format

Jerry Over a year ago

DON'T use str for variable names because this overrides the str() function.

Francisco F Over a year ago

I have a problem, the word is in utf-8 and this gives me an error.

Kasravnd Over a year ago

@FranciscoF What kind of error? you can also use re.U flag in findall function!

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