用字母序列替换python中的字符串[重复]

Question

我正在编写一段 python 代码来替换一个字母序列。我知道该怎么做，但不幸的是它只是替换了已经替换的那个。

lines=[]
replacements = {'a':'s','s':'d','d':'f','f':'g','g':'h','h':'j','j':'k','k':'l'}

with open("wrongString.txt") as infile:
    for line in infile:
        for src,target in replacements.iteritems():
            line = line.replace(src,target)
        lines.append(line)

with open("decode.txt","w") as outfile:
        for line in lines:              
            outfile.write(line)

wrongstring.txt : asdfghjkl

运行代码后，结果显示（encode.txt）：ggggkkkll

代码确实将“a”替换为“s”，并不断将“s”替换为“d”，直到以某种方式得到“g”。我只想将“a”替换为“s”然后停止替换它。

你们能帮我找到解决办法吗？

感谢您的回答！

Answer 1

使用 list comp 这样您就不会覆盖任何替换的字符：

  line = "".join([replacements.get(ch, ch) for ch in line])

你也不需要存储所有的行，只要你去写行：

with open("wrongString.txt") as infile, open("decode.txt","w")  as outfile:
    outfile.writelines("".join([replacements.get(ch,ch) 
                                  for ch in line]) for  line in infile))