How to match a string in a sentence

Question

I want to check if a particular string is present in a sentence. I use simple code for this

subStr = 'joker' Sent = 'Hello World I am Joker' if subStr.lower() in Sent.lower(): print('found') 

This is a simple approach, but it does not work when a sentence appears as

hello world I'm joyer

hello world I'm Oker

When I parse a sentence from a PDF file, unnecessary spaces appear here and there.

A simple approach to solving this problem would be to remove all spaces from the sentence and search for matching substrings. I want to know the thoughts of other peoples on this issue, should I take this approach or look for other alternatives.

Answer 1

This is more efficient than replace for small strings, more expensive for large strings. He will not deal with controversial cases, for example. 'to day' versus 'today'.

 subStr in ''.join(Sent.split()).lower() # True 

Answer 2

you can use regex:

 import re word_pattern = re.compile(r'j\s*o\s*k\s*e\s*r', re.I) sent = 'Hello World I am Joker' if word_pattern.search(sent): print('found') 

I hope this works

Answer 3

Try it. It may break unexpectedly. But for your use case, this may work.

 In [1]: Sent = 'Hello World I am Joker' In [3]: subStr = 'Joker' In [4]: if subStr in Sent.replace(' ', ''): ...: print("Do something") ...: Do something 

Answer 4

Your proposed approach - removing spaces - seems simple and effective (two to ten times faster than other suggestions in some simple tests). If you need to minimize false positives, however, you might be better off with a regex approach. You can add word boundaries to avoid partial word matches, and examine the matching substring to see if any spaces can be real spaces, possibly by matching with a canonical list of words.

 >>> sentence = 'Were the fields ever green? - they were never green.' >>> target = 'evergreen' >>> pattern = re.compile(r'\b' + '\s*'.join(target) + r'\b') >>> pattern.findall(sentence) # only one match because of \b ['ever green'] >>> matching_words = pattern.findall(sentence)[0].split() >>> all(word in dictionary for word in matching_words) True