如何避免在python中对文本文件进行重复输入

lines = set()
with open('file.txt', 'r') as file:
    for line in file:
        lines.add(line.strip())

lines = {}
with open('file.txt', 'r') as file:
    for line in file:
        lines[line.strip()] = None

with open('file.txt', 'r') as file:
    lines = list({line.strip() for line in file})