Question

我有一个文件-

First Line
Second Line
Third Line
Fourth Line
Fifth Line
Sixth Line

现在，我想在第四行之后写入文件的内容。因此新文件将是-

Fifth Line
Sixth Line

我的尝试-

cnt=0
for root, dirs, files in os.walk(currentdir):
    for name in files:



        f = open(root+"/"+name,'r')
        lines = f.readlines()
        f.close()
        f = open(os.path.join(root, name),"w")
        for line in lines:
            cnt+=1 
            if line =="fourth Line"+"\n":
                break:
        f.seek(cnt)
        f.write(line)
        f.close()

Answer 1

for path, dirs, files in os.walk(currentdir):
    for name in files:
        with open(os.path.join(path, name)) as f:
            data = f.readlines()
        pos = data.index("Fourth Line\n")
        with open(os.path.join(path, name), 'w') as f:
            f.writelines(data[pos:])

Answer 2

您只需将行存储在文件中，对数组进行切片，然后将其写回：

with open('filename.txt', 'r+') as f:
    lines = f.readlines()
    f.write(lines[5:])

如果需要，可以在单独的with块中或在其他任何块中进行读写。

Answer 3

您可以将文件行加载到列表中，然后在拆分列表后仅保留所需的行并保存在文件中。例如，如果您想要第四行之后的内容：

f = open("file.txt", 'r')
lines = f.readlines()
f.close()
lines = lines[4:]
f = open("file.txt", 'w')
f.write(lines)
f.close()

Answer 4

您总是可以将一个计数器放在循环中，并在计数器达到4时开始写第二个文件。

with open('a', 'w') as a, open('b', 'w') as b:
do_something()

或：

f1 = open(path, 'w')
f1.write(data)
f1.close()
counter += 1
if counter >= 4:
f2 = open(path, 'w')
f2.write(data)
f2.close()

删除特定行python之前的所有行

4 个答案: