读取文件然后在 Python 中覆盖它

Question

我一直在尝试读取一个文件，然后用一些更新的数据覆盖它。我试过这样做：

#Created filename.txt with some data
with open('filename.txt', 'r+') as f:
    data = f.read()
    new_data = process(data)  # data is being changed
    f.seek(0)
    f.write(new_data)

出于某种原因，它不会覆盖文件，文件内容保持不变。

Answer 1

您应该添加对 truncate after seek as 建议的调用。

尝试在不同的范围内读取和写入，这样代码更清晰，并且在打开文件处理程序时不进行数据处理。

data = ''
with open('filename.txt', 'r') as f:
    data = f.read()

new_data = process(data)  
with open('filename.txt', 'w+') as f:
    f.write(new_data)

Answer 2

搜索到前面后截断文件。这将删除所有现有数据。

>>> open('deleteme', 'w').write('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa')
>>> f = open('deleteme', 'r+')
>>> f.read()
'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
>>> f.seek(0)
>>> f.truncate()
>>> f.write('bbb')
>>> f.close()
>>> open('deleteme').read()
'bbb'
>>>

读取文件然后在 Python 中覆盖它

Reading a file and then overwriting it in Python

python

patch

file

overwrite

readfile