why doesn't replaceAll work? - 未名空间MITBBS历史存档

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why doesn't replaceAll work?

why doesn't replaceAll work?# Java - 爪哇娇娃

m*r2004-09-16 07:09

1 楼

String foo = '\' + '\';
foo.replaceAll("\\\\", "\\");
would cause an indexOutOfBounds exception.... i don't understand.

Q*g2004-09-16 07:09

2 楼

看API啊。
我猜你是想要把两个backslashes换成一个是吧？应该这么写：
String foo = "\\" + "\\";
foo.replaceAll("\\\\\\\\", "\\\\");
replaceAll的第一个参数是regular expression。regular expression里
要用两个backslash '\\' 表示单个字符 '\'。然后因为你在java里头写字符串
常量也是'\\'表示一个'\'。所以第一个参数需要一共8个'\'。
第二个参数里头'\'也是有特殊含义的，所以也是。。。。
Note that backslashes (\) and dollar signs ($) in the replacement
string may cause the results to be different than if it were being
treated as a literal replacement string. Dollar signs may be
treated as references to captured subs

【在 m****r 的大作中提到】

: String foo = '\' + '\';
: foo.replaceAll("\\\\", "\\");
: would cause an indexOutOfBounds exception.... i don't understand.

A*o2004-09-16 07:09

3 楼

'\' + '\' --> '\' + "" + '\'

【在 m****r 的大作中提到】

: String foo = '\' + '\';
: foo.replaceAll("\\\\", "\\");
: would cause an indexOutOfBounds exception.... i don't understand.

m*r2004-09-16 07:09

4 楼

i got the first "\\\\\\\\", but thought the second part was just a normal
java string. anyway, thx, it works now.

【在 Q**g 的大作中提到】

: 看API啊。
: 我猜你是想要把两个backslashes换成一个是吧？应该这么写：
: String foo = "\\" + "\\";
: foo.replaceAll("\\\\\\\\", "\\\\");
: replaceAll的第一个参数是regular expression。regular expression里
: 要用两个backslash '\\' 表示单个字符 '\'。然后因为你在java里头写字符串
: 常量也是'\\'表示一个'\'。所以第一个参数需要一共8个'\'。
: 第二个参数里头'\'也是有特殊含义的，所以也是。。。。
: Note that backslashes (\) and dollar signs ($) in the replacement
: string may cause the results to be different than if it were being