Remove blank lines from a .txt file

clear_text_lines.py

# Before checking we strip leading and trailing characters
# Check if the line is not empty
with open("empty.txt", 'r') as inp, open('out.txt', 'w') as out:
    for line in inp:
        if line.strip():
            out.write(line)
 
# Before checking we strip only trailing characters
# Check if the line is not empty
with open("empty.txt", 'r') as inp, open('out.txt', 'w') as out:
    for line in inp:
        if line.rstrip():
            out.write(line)
 
# Check if the length is greater than zero
with open("empty.txt", 'r') as inp, open('out.txt', 'w') as out:
    for line in inp:
        if len(line.strip()) > 0:
            out.write(line)
 
# Check if the line is not a new line
with open("empty.txt", 'r') as inp, open('out.txt', 'w') as out:
    for line in inp:
        if line != '\n':
            out.write(line)
 
# Check if the line is not a space using a built in function
with open("empty.txt", 'r') as inp, open('out.txt', 'w') as out:
    for line in inp:
        if not line.isspace():
            out.write(line)
 
# Check if the line is not white space using regular expressions
import re
with open("empty.txt", 'r') as inp, open('out.txt', 'w') as out:
    for line in inp:
        if re.search('\S', line):
            out.write(line)