Python to print string from substring from list

Question

I am a newbie to python.Consider I have a list ['python','java','ruby']

I have a textfile as:

jrubyk
knwdjavawe
weqkpythonqwe
1ruby.e

Expected output:

ruby
java
python
ruby

I need to print the strings in list hidden inside as substring. Is there a way to obtain that?

No if you dont have a database or a reference as you are giving with the words you are expecting to output. If you do, it doesnt make sense. You dont need the file to do so. Just iterate over the items and print them — wonderwhy
– wonderwhy, Commented Sep 5, 2014 at 16:21
@ShashankAgarwal maybe he wasnt able to do anything . Anyway, what he is trying to do is no way useful but to practice the programming language — wonderwhy
– wonderwhy, Commented Sep 5, 2014 at 16:23
I've changed the sample input in the question to make the point clear. — Basilevs
– Basilevs, Commented Sep 6, 2014 at 15:32

Aphid · Accepted Answer · 2014-09-05 16:40:16Z

2

I tend to use regular expressions when I want to strip certain substrings from larger strings. Here is an inelegant but readable way to do this.

import re

python_matcher = re.compile('python')
java_matcher = re.compile('java')
ruby_matcher = re.compile('ruby')

hidden_text_list = open('hidden.txt', 'r').readlines()

for line in hidden_text_list:
    python_matched = python_matcher.search(line)
    java_matched = java_matcher.search(line)
    ruby_matched = ruby_matcher.search(line)

    if python_matched:
        print python_matched.group()
    elif java_matched:
        print java_matched.group()
    elif ruby_matched:
        print ruby_matched.group()

answered Sep 5, 2014 at 16:40

Aphid

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3 Comments

Adam Smith Over a year ago

Ooh this is fun! Very good for a long list, not so great for a short list of hidden words. Try all_matcher = re.compile("|".join([re.escape(word) for word in hidden_words])) for line in textfile: print(" ".join(all_matcher.findall(line)))

Aphid Over a year ago

I'll leave the answer here, but in hindsight I like yours much better. More concise. I started to get froggy on the regex objects, but wanted OP to be able to understand what was going on. I really like your findall method, though.

Adam Smith Over a year ago

Feel free to edit mine in as an alternative. I didn't even consider regex here, oops!

Adam Smith · Accepted Answer · 2014-09-05 16:21:47Z

1

The brute force approach is:

hidden_strings = ['python','java','ruby']
with open('path/to/textfile/as/in/example.txt') as infile:
    for line in infile:
        for hidden_string in hidden_strings:
            if hidden_string in line:
                print(hidden_string)

answered Sep 5, 2014 at 16:21

Adam Smith

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3 Comments

Adam Smith Over a year ago

@wonderwhy The question makes perfect sense. He has a list of hidden words and a textfile with gobble-dee-gook that contains hidden words in it. He's trying pull his hidden words out of the cough "ENCRYPTED" text file.

wonderwhy Over a year ago

But why to search the words inside the file if you already have them, @AdamSmith?

Adam Smith Over a year ago

@wonderwhy "Why" isn't really a valid question here, but it seems like he's pulling a message from the textfile, not the list....

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