CODEWITHSUNDEEP
pythonstringpython-2.7listsearch
Kfir Cohen
Kfir Cohen

Reputation: 153

Searching for multiple strings in a file by using a list of strings

I am attempting to somehow search for multiple strings and perform a certain action when a certain string is found. Is it possible to provide a list of strings and go through the file searching for any of the strings that are present in that list?

list_of_strings_to_search_for = ['string_1', 'string_2', 'string_3']

I'm currently doing it one-by-one, indicating every string I want to search for in a new if-elif-else statement, like so:

with open(logPath) as file:
    for line in file:
        if 'string_1' in line:
            #do_something_1
        elif 'string_2' in line:
            #do_something_2
        elif 'string_3' in line:
            #do_something_3
        else:
            return True

I have tried passing the list itself, however, the "if x in line" is expecting a single string, and not a list. What is a worthy solution for such a thing?

Thank you.

Upvotes: 3

Views: 6535

Answers (3)

Ivan Kovacevic
Ivan Kovacevic

Reputation: 1332

Here is one way to do it with the regular expressions re module included with Python:

import re

def actionA(position):
    print 'A at', position

def actionB(position):
    print 'B at', position

def actionC(position):
    print 'C at', position

textData = 'Just an alpha example of a beta text that turns into gamma'

stringsAndActions = {'alpha':actionA, 'beta':actionB ,'gamma':actionC}
regexSearchString = str.join('|', stringsAndActions.keys())

for match in re.finditer(regexSearchString, textData):
    stringsAndActions[match.group()](match.start())

prints out:

A at 8
B at 25
C at 51

Upvotes: 0

Ricardo
Ricardo

Reputation: 597

If you don't want to write several if-else statements, you can create a dict that stores the strings you want to search as keys, and the functions to execute as values.

For example:

logPath = "log.txt"

def action1():
    print("Hi")

def action2():
    print("Hello")

strings = {'string_1': action1, 'string_2': action2}

with open(logPath, 'r') as file:
    for line in file:
        for search, action in strings.items():
            if search in line:
                action()

With a log.txt like:

string_1
string_2
string_1

The ouput is:

hello
hi
hello

Upvotes: 3

Wonjin
Wonjin

Reputation: 432

loop your string list, instead of if/else

list_of_strings_to_search_for = ['string_1', 'string_2', 'string_3']

with open(logPath) as file:
    for line in file:
        for s in list_of_strings_to_search_for:
            if s in line:
                #do something
                print("%s is matched in %s" % (s,line))

Upvotes: 2

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