Appending Specific Lines from a File, inside For Loop to open each file

January 12, 2022

I have 4 folders full of txt documents. I used the code below to extract all the txt and append them to a list.

Doc1 = glob.glob('path*.txt')
Doc2 = glob.glob('path*.txt')
Doc3 = glob.glob('path*.txt')
Doc4 = glob.glob('path*.txt')

lines = []

for file in Doc1:     ### repeated this block for Doc2, Doc3 and Doc4 ####
     f = open(file,'r')
     lines.append(f.readlines())
     f.close()

This code above worked just fine. However, now what I want to do is:

for each txt document in the folder, I only want to append the lines between a start and an end, to get rid of unnecessary text. The start and end text will be the same for every document in all the folders. I tried to do this:

for file in Doc1:
     f = open(file,'r')                    #this opens the file
     for line in file:                     #for each line in the file
         tag = False                       #tag set to False, initially
        if line.startswith('text'):        #if it starts with this text then:
             tag = True                    #tag changes to True
        elif 'end text' in line:           #if it this text is in the line then:
             tag = False                   #tag stays false
             lines.append(f.readlines())   #append this line (but now tag stays False)
        elif tag:                          # if tag is true, then append that line
             lines.append(f.readlines())
    f.close()

This code runs, as in, I do not get any warnings or errors. But no lines append to Lines. TIA for any advice and assistance.

>Solution :

The tag is reset on every iteration which means that it never outputs anything other than a line that has end text in it. Also, some reordering of the operations is needed.

lines = []
for p in Doc1:
    tag = False  # Set the initial tag to False for the new file.
    with open(p, 'r') as f:
        for line in f:
            if tag:  # First line will never be printed since it must be a start tag
                lines.append(line)
            if  line.startswith('start'):  # Start adding from next line
                tag = True
            elif 'end' in line:  # Already added the line so we can reset the tag
                tag = False