CODEWITHSUNDEEP
pythonstring
Kaiser
Kaiser

Reputation: 39

Python - Find words in string

I know that I can find a word in a string with

if word in my_string:

But I want to find all "word" in the string, like this.

counter = 0
while True:
    if word in my_string:
        counter += 1

How can I do it without "counting" the same word over and over again?

Upvotes: 1

Views: 26351

Answers (4)

Brendan Abel
Brendan Abel

Reputation: 37549

Use regular expressions:

import re

word = 'test'
my_string = 'this is a test and more test and a test'

# Use escape in case your search word contains periods or symbols that are used in regular expressions.
re_word = re.escape(word)

# re.findall returns a list of matches
matches = re.findall(re_word, my_string)

# matches = ['test', 'test', 'test']
print len(matches) # 3

Be aware that this will catch other words that contain your word like testing. You could change your regex to just match exactly your word

Upvotes: 0

R Nar
R Nar

Reputation: 5515

If you want to make sure that it counts a full word like is will only have one in this is even if there is an is in this, you can split, filter and count:

>>> s = 'this is a sentences that has is and is and is (4)'
>>> word = 'is'
>>> counter = len([x for x in s.split() if x == word])
>>> counter
4

However, if you just want count all occurrences of a substring, ie is would also match the is in this then:

>>> s = 'is this is'
>>> counter = len(s.split(word))-1
>>> counter
3

in other words, split the string at every occurrence of the word, then minus one to get the count.

Edit - JUST USE COUNT:

It's been a long day so I totally forgot but str has a built-in method for this str.count(substring) that does the same as my second answer but way more readable. Please consider using this method (and look at other people's answers for how to)

Upvotes: 4

OnGle
OnGle

Reputation: 132

String actually already has the functionality you are looking for. You simply need to use str.count(item) for example.

EDIT: This will search for all occurrences of said string including parts of words. 

string_to_search = 'apple apple orange banana grapefruit apple banana'

number_of_apples = string_to_search.count('apple')
number_of_bananas = string_to_search.count('banana')

The following will search for only complete words, just split the string you want to search.

string_to_search = 'apple apple orange banana grapefruit apple banana'.split()

number_of_apples = string_to_search.count('apple')
number_of_bananas = string_to_search.count('banana')

Upvotes: 2

Chad S.
Chad S.

Reputation: 6631

Use the beg argument for the .find method.

counter = 0
search_pos = 0
while True:
    found = my_string.find(word, search_pos)
    if found != -1: # find returns -1 when it's not found
        #update counter and move search_pos to look for the next word
        search_pos = found + len(word)
        counter += 1
    else:
        #the word wasn't found
        break

This is kinda a general purpose solution. Specifically for counting in a string you can just use my_string.count(word)

Upvotes: 2

Related Questions