Question

所以我有文件：data2.txt

Lollypop,
Lolly pop,
ooh 
lolly,
lolly, lolly;
lollypop, lollypop,
ooh lolly, lolly, lolly,
lollypop!
ba dum dum dum ...

LOL :-)

我需要循环遍历data2.txt的每一行，只打印包含字符串＆lt; lol＆＃39;并将输出打印到新文件

with open("data3.txt") as g:
    with open("data2.txt") as lfp:
        for lin in lfp:
            if 'lol' in lin:
                g.write(str(lin))
            elif 'LOL' in lin:
                g.write(str(lin))
            elif 'Lol' in lin:
                g.write(str(lin))

但我一直收到错误：

    g.write(str(lin))
io.UnsupportedOperation: not writable

Answer 1

您需要打开w进行撰写：

with open("data3.txt","w") as g:
    with open("data2.txt") as lfp:

您还可以简化为：

with open("data3.txt", "w") as g, open("data2.txt") as lfp:
        for lin in lfp:
            if 'lol' in lin.lower():
                g.write(lin)

或使用writelines：

with open("data3.txt", "w") as g, open("data2.txt") as lfp:
        g.writelines(line for line in lfp if "lol" in line.lower())

line已经是一个字符串，因此您无需在其上调用str，使用"lol" in line.lower()将匹配所有案例。

如果您明确地寻找"lol", "Lol", "LOL"，那么any将是一种更好的方法。

with open("data3.txt", "w") as g, open("data2.txt") as lfp:
    poss = ("lol", "Lol", "LOL")
    g.writelines(line for line in lfp 
                    if any(s in line for s in poss))

所有模式都在docs

中说明

Answer 2

问题在于行with open("data3.txt") as g:

您未向open提供模式，默认为r，仅供阅读。如果要替换文件（如果文件已存在），请使用with open("data3.txt", 'w') as g:;如果要存在，请使用with open("data3.txt", 'a') as g: {。{}}

如何将输出写入文件python

2 个答案: