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

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.

CodePudding user response：

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

CodePudding user response：

this is because you are using the line, is the file ,in string form, not readed, to do this you can do:

for line in f:
   # write code here

so your code becomes like this:

import glob
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:
     f = open(file,'r')                    #this opens the file
     for line in f:                     #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()