搜索文本文件并在Python中打印相关行？

Question

如何在文本文件中搜索关键短语或关键字，然后打印该关键短语或关键字所在的行？

Answer 1

searchfile = open("file.txt", "r")
for line in searchfile:
    if "searchphrase" in line: print line
searchfile.close()

打印出多行（以一种简单的方式）

f = open("file.txt", "r")
searchlines = f.readlines()
f.close()
for i, line in enumerate(searchlines):
    if "searchphrase" in line: 
        for l in searchlines[i:i+3]: print l,
        print

逗号print l,防止输出中出现多余的空格。尾随的打印语句将结果划分为不同的行。

或者更好（从Mark Ransom偷回来）：

with open("file.txt", "r") as f:
    searchlines = f.readlines()
for i, line in enumerate(searchlines):
    if "searchphrase" in line: 
        for l in searchlines[i:i+3]: print l,
        print