在Python中覆盖文件中的字符

使用fileinput和

inplace=True

import fileinputimport sysfor line in fileinput.input("test.txt",inplace=True):    # replaces all occurrences of apples in each line with oranges    sys.stdout.write(line.replace("apples","oranges"))

输入：

Marry has 10 carrotsBob has 15 applesTom has 4 bananas

输出：

Marry has 10 carrotsBob has 15 orangesTom has 4 bananas

使用re避免匹配子字符串：

import fileinputimport sysimport re# use word boundaries so we only match "apples"  r = re.compile(r"bapplesb")for line in fileinput.input("test.txt",inplace=True):    # will write the line as is or replace apples with oranges and write    sys.stdout.write(r.sub("oranges",line))

删除所有遗留词：

import fileinputimport sysfor line in fileinput.input("test.txt",inplace=True):    # split on the last whitespace and write everything up to that    sys.stdout.write("{}n".format(line.rsplit(None, 1)[0]))

输出：

Marry has 10Bob has 15Tom has 4

您还可以使用tempfile.NamedTemporaryFile使用以上任何逻辑将更新后的行写入，然后使用shutil.move替换原始文件：

from tempfile import NamedTemporaryFilefrom shutil import movewith open("test.txt") as f, NamedTemporaryFile("w",dir=".", delete=False) as temp:    for line in f:        temp.write("{}n".format(line.rsplit(None, 1)[0]))# replace original file with updated contentmove(temp.name,"test.txt")

您需要通过

dir="."

delete=False

.name