Why can’t the concatenated variable 'new_path' work but the whole string 'full

I tried to figure out whether some images stored by the name in a text file exists in a specific image folder.

The text file looks like this (including 1k lines) :

4916849840_43930a0979_o.png

331595384_492146dbf3_k.png

13517809023_f49228b3ec_o.png

So I wrote the code like:

import os

txt_path = '/Users/owner/Desktop/360_dataset_3k/train/train_3k_1.txt'
images_path = '/Users/owner/Desktop/360_dataset_3k/360_512_3k_1/'
full_path = '/Users/owner/Desktop/360_dataset_3k/360_512_3k_1/27107804622_984dbb2181_o.png'

f = open(txt_path,"r")
lines = f.readlines()
for line in lines:
    new_path = os.path.join(images_path, line)
    print(new_path)
    if os.path.exists(new_path):
        print("True.\n")
    else:
        print("False.\n")

However, the outputs are endless False. BUT, when I replaced the new_path here

if os.path.exists(new_path):
        print("True.\n")

with the variable full_path which is a print of new_path created by a line in lines.

if os.path.exists(full_path):
        print("True.\n")

The outputs are True!!!

And after checking in a rather tedious way, it turns out they do exist in the image folder. Can somebody tell me what is going on please? THANKS SO MUCH.

CodePudding user response：

When you call the readlines() method for file object, each line has a newline character ('\n') at the end. You need to strip line before joining the path.

Code:

f = open(txt_path,"r")
lines = f.readlines()
for line in lines:
    line = line.strip()  #Remove whitespace
    new_path = os.path.join(images_path, line)
    print(new_path)
    if os.path.exists(new_path):
        print("True.\n")
    else:
        print("False.\n")

Also close file object f.close() when task is done.