如何从我的代码根据包含特定字符串选择的文本文件的行打印元素？

Question

I am new to python, and I am trying to figure out a problem. So I have 2 text files; the first one contains a word (I started with one word for simplicity), I read that word, assign it onto a string variable, then look for this word in tens of thousands of lines in my 2nd text file. This part I have completed. Now onto my issue.

The 2nd text file contains 4 columns, for the sake of keeping things simple, I'll give an example below:

Alpha 100 200 thewordiamlookingforisapple
Beta 200 300 thewordiamnotlookingforispear
Gamma 300 400 onceagainapple
Theta 400 500 onceagainapple
Omega 500 600 andonceagainpear

Let's say that I am looking for the string "apple" and lines 1,3 and 4 contain it. Now I want to print the 1st, 2nd, and 3rd columns of the associated lines.

My code so far is this:

def word_match(File, String):
    wordnumber = 0
    listOfAssociatedWords = []
    with open(File, 'r') as read_obj:
        for line in read_obj:
            wordnumber += 1
            if String in line:
                listOfAssociatedWords.append((wordnumber, line.rstrip()))

    return listOfAssociatedWords
#------------------------------------------------------------------------------
firstfile = open("/Directory/firstfilename", "r")
String = firstfile.read()

firstfile.close()
#------------------------------------------------------------------------------
matched_words = word_match("/Directory/secondfilename", word)
print('Total Matched Words : ', len(matched_words))
for elem in matched_words:
    print('Word Number = ', elem[0], ' :: Line = ', elem[1])

Current Output:
('Total Matched Words : ', 3)
('Word Number = ', 1, ' :: Line = ', 'Alpha 100 200 thewordiamlookingforisapple')
('Word Number = ', 3, ' :: Line = ', 'Gamma 300 400 onceagainapple')
('Word Number = ', 4, ' :: Line = ', 'Theta 400 500 onceagainapple')


Desired Output:
Alpha 100 200
Gamma 300 400
Theta 400 500

Answer 1

I think you want this

def word_match(File, String):
    wordnumber = 0
    listOfAssociatedWords = []
    with open(File, 'r') as read_obj:
        for line in read_obj:
            wordnumber += 1
            if String in line:
                listOfAssociatedWords.append(line.split()[:3])

    return listOfAssociatedWords

Answer 2

Another easy way to do this is to use pandas. You may read your file into a pandas dataframe. This way later if you want to add more complexity to the logic, it would be fairly easy. Using pandas you can achieve the expected results as :

import pandas as pd

initial_word = 'apple'

sample_dict = {'col1': ['Alpha', 'Beta', 'Gamma', 'Theta', 'Omega'], 'col2': [100, 200, 300, 400, 500],
                'col3': [200, 300, 400, 500, 600],
                'col4': ['thewordiamlookingforisapple', 'thewordiamnotlookingforispear', 'onceagainapple', 'onceagainapple', 'andonceagainpear']}
df = pd.DataFrame(data=sample_dict)

print(df)
new_df = df[df['col4'].str.contains(initial_word)]
new_df = new_df.drop('col4', 1)
print(new_df)

The output would look like (for df):

 col1  col2  col3                           col4
0  Alpha   100   200    thewordiamlookingforisapple
1   Beta   200   300  thewordiamnotlookingforispear
2  Gamma   300   400                 onceagainapple
3  Theta   400   500                 onceagainapple
4  Omega   500   600               andonceagainpear

And for new df:

    col1  col2  col3
0  Alpha   100   200
2  Gamma   300   400
3  Theta   400   500

You can read the txt file and convert to a pandas dataframe initially.