使用字典替换文本文件中的单词

Question

我正在尝试打开一个文本文件，然后通读它，用存储在字典中的字符串替换某些字符串。

根据对How do I edit a text file in Python? 的回答，我可以在替换之前提取字典值，但循环遍历字典似乎更有效。

代码不会产生任何错误，也不会做任何替换。

import fileinput

text = "sample file.txt"
fields = {"pattern 1": "replacement text 1", "pattern 2": "replacement text 2"}

for line in fileinput.input(text, inplace=True):
    line = line.rstrip()
    for i in fields:
         for field in fields:
             field_value = fields[field]

             if field in line:
                  line = line.replace(field, field_value)


             print line

Answer 1

我使用items() 来迭代您的fields 字典中的key 和values。

我用continue 跳过空白行，用rstrip() 清理其他空白行

我将line 中的每个keys 替换为fields 字典中的values，并用print 编写每一行。

import fileinput

text = "sample file.txt"
fields = {"pattern 1": "replacement text 1", "pattern 2": "replacement text 2"}


for line in fileinput.input(text, inplace=True):
    line = line.rstrip()
    if not line:
        continue
    for f_key, f_value in fields.items():
        if f_key in line:
            line = line.replace(f_key, f_value)
    print line

Answer 2

如果您可以找到覆盖所有键的正则表达式模式，则可以使用re.sub 来获得非常有效的解决方案：您只需要一次通过，而不是为每个搜索词解析整个文本。

在您的标题中，您提到了“替换单词”。在这种情况下，'\w+' 可以正常工作。

import re

fields = {"pattern 1": "replacement text 1", "pattern 2": "replacement text 2"}

words_to_replace = r'\bpattern \d+\b'

text = """Based on answers to How do I edit a text file in Python? pattern 1 I could pull out
the dictionary values before doing the replacing, but looping through the dictionary seems more efficient.
Test pattern 2
The code doesn't produce any errors, but also doesn't do any replacing. pattern 3"""

def replace_words_using_dict(matchobj):
    key = matchobj.group(0)
    return fields.get(key, key)

print(re.sub(words_to_replace, replace_words_using_dict, text))

它输出：

Based on answers to How do I edit a text file in Python? replacement text 1 I could pull out
the dictionary values before doing the replacing, but looping through the dictionary seems more efficient.
Test replacement text 2
The code doesn't produce any errors, but also doesn't do any replacing. pattern 3

另外，在原地修改文件时要非常小心。我建议你用替换写第二个文件。一旦您 100% 确定它可以完美运行，您就可以切换到 inplace=True。

Answer 3

刚刚弄清楚如何通过遍历字典（仅匹配整个单词）一次性替换 txt 文件中的许多不同单词。 如果我想用“John”替换“1”，但最终将“12”变成“John2”，那会很烦人。以下代码对我有用。

import re

match = {}  # create a dictionary of words-to-replace and words-to-replace-with

f = open("filename","r")
data = f.read() # string of all file content

def replace_all(text, dic):
    for i, j in dic.items():
        text = re.sub(r"\b%s\b"%i, j, text) 
        # r"\b%s\b"% enables replacing by whole word matches only
    return text

data = replace_all(data,match)
print(data) # you can copy and paste the result to whatever file you like

Answer 4

如果你对 Python 比较熟悉，可以参考官方文档中的提示：

7.1. string — Common string operations

还有 subclass，即 Template 类，您可以在其中以某种方式定义每个单独的世界都将是一个新的 placeholder，然后使用 @ 987654322@您可以获得一个不错且可靠的解决方案。

Answer 5

import fileinput

text = "sample file.txt"
fields = {"pattern 1": "replacement text 1", "pattern 2": "replacement text 2"}

for line in fileinput.input(text, inplace=True):
    line = line.rstrip()
    for field in fields:
        if field in line:
            line = line.replace(field, fields[field])

    print line

Answer 6

我会这样做：

fields = {"pattern 1": "replacement text 1", "pattern 2": "replacement text 2"}

with open('yourfile.txt', 'w+') as f:
    s = f.read()
    for key in fields:
        s = s.replace(key, fields[key])
    f.write(s)