Removing lines above specific line in text in python

Question

I have text like this

ABC 
DEF
Ref.By
AAA
AAA

I want remove all the line before the line Ref.By.

How can I do it in python ?

Answer 1

Try this

text_str = """ABC
DEF
Ref.By
AAA
AAA"""

text_lines = text_str.split("\n")

idx = text_lines.index("Ref.By") + 1

result_text = "\n".join(text_lines[idx:])

print(result_text)

Answer 2

lines = open('your_file.txt', 'r').readlines()
search = 'Ref.By'
for i, line in enumerate(lines):
    if search in line:
        break

if i < len(lines) - 1:
    with open('your_file.txt', 'w') as f:
        f.write('\n'.join(lines[i + 1:]))

This is alright provided your file size is well within 2-4 MB. It becomes problematic to store it in memory beyond that point.