仅替换第一次出现的字符串？

Question

我有这样的事情:

text = 'This text is very very long.'
replace_words = ['very','word']

for word in replace_words:
    text = text.replace('very','not very')

我想只替换第一个'非常'或选择哪个'非常'被覆盖.我在更大量的文本上这样做,所以我想控制重复单词的替换方式.

Answer 1

text = text.replace("very", "not very", 1)

>>> help(str.replace)
Help on method_descriptor:

replace(...)
    S.replace (old, new[, count]) -> string

    Return a copy of string S with all occurrences of substring
    old replaced by new.  If the optional argument count is
    given, only the first count occurrences are replaced.

Answer 2

text = text.replace("very", "not very", 1)

第三个参数是要替换的最大出现次数.
从Python的文档:

string.replace(s,old,new [,maxreplace])
返回字符串s的副本,其中所有出现的substring old都替换为new.如果给出了可选参数maxreplace,则替换第一个maxreplace事件.

Answer 3

来自http://docs.python.org/release/2.5.2/lib/string-methods.html：

replace( old, new[, count])
返回字符串的副本，其中所有出现的子字符串 old 都被 new 替换。如果给出了可选参数计数，则仅替换第一个计数出现。

我没有尝试，但我相信它有效