单线：
open("out1.txt", "w").writelines([l for l in open("in.txt").readlines() if "tests/file/myword" in l])推荐搭配
with：
with open("in.txt") as f: lines = f.readlines() lines = [l for l in lines if "ROW" in l] with open("out.txt", "w") as f1: f1.writelines(lines)使用更少的内存：
with open("in.txt") as f: with open("out.txt", "w") as f1: for line in f: if "ROW" in line: f1.write(line)
