write output from print to a file in python

Question

I have a code that reads multiple text files and print the last line.

from glob import glob
text_files = glob('C:/Input/*.txt')
for file_name in text_files:
       with open(file_name, 'r+') as f:
           lines = f.read().splitlines()
           last_line = lines[-3]
           print (last_line)

I want to redirect the print to an output txt file, so that i will check the sentence. Also the txt files has multiple lines of space. I want to delete all the empty lines and get the last line of the file to an output file. When i try to write it is writing only the last read file. Not all files last line is written.

Can someone help?

Thanks, Aarush

Answer 1

Instead of just print, do something like this:

print(last_line)
with open('output.txt', 'w') as fout:
    fout.write(last_line)

Or you could also append to the file!

Answer 2

I think you have two separate questions.
Next time you use stack overflow, if you have multiple questions, please post them separately.

Question 1

How do I re-direct the output from the print function to a file?
For example, consider a hello world program:

 print("hello world")

How do we create a file (named something like text_file.txt ) in the current working directory, and output the print statements to that file?

ANSWER 1

Writing output from the print function to a file is simple to do:

with open ('test_file.txt', 'w') as out_file:
    print("hello world", file=out_file)    

Note that print function accepts a special keyword-argument named " file "
You must write file=f in order to pass f as input to the print function.

QUESTION 2

How do I get the last non-blank line from s file? I have an input file which has lots of line-feeds, carriage-returns, and space characters at the end of. We need to ignore blank lines, and retrieve the last lien of the file which contains at least one character which is not a white-space character.

Answer 2

def get_last_line(file_stream):   
    for line in map(str, reversed(iter(file_stream))):

        # `strip()` removes all leading a trailing white-space characters
        # `strip()` removes `\n`, `\r`, `\t`, space chars, etc...

        line = line.strip()
        
        if len(line) > 0:
            return line

     # if the file contains nothing but blank lines
     # return the empty string
     return ""

You can process multiple files like so:

file_names = ["input_1.txt", "input_2.txt", "input_3.txt"]

with  open ('out_file.txt', 'w') as out_file:
    for file_name in file_names:
       with open(file_name, 'r') as read_file:
           last_line = get_last_line(read_file)
           print (last_line, file=out_file)