我想替换字符串中特定单词的多次出现并只保留最后一个。
"How about a how about b how about c" to ==>
"a b How about c"
我使用 string.replace 替换所有出现,但我仍然想要最后一个。对不起,如果它很天真
我想替换字符串中特定单词的多次出现并只保留最后一个。
"How about a how about b how about c" to ==>
"a b How about c"
我使用 string.replace 替换所有出现,但我仍然想要最后一个。对不起,如果它很天真
一种方法是使用某种循环来检查是否发生了任何事情。
function allButLast(haystack, needle, replacer, ignoreCase) {
var n0, n1, n2;
needle = new RegExp(needle, ignoreCase ? 'i' : '');
replacer = replacer || '';
n0 = n1 = n2 = haystack;
do {
n2 = n1; n1 = n0;
n0 = n0.replace(needle, replacer);
} while (n0 !== n1);
return n2;
}
allButLast("How about a how about b how about c", "how about ", '', 1);
// "a b how about c"
稍微不同的方法,同时支持 RegExp 和普通字符串针:
var replaceAllBarLast = function(str, needle, replacement){
var out = '', last = { i:0, m: null }, res = -1;
/// RegExp support
if ( needle.exec ) {
if ( !needle.global ) throw new Error('RegExp must be global');
while( (res = needle.exec(str)) !== null ) {
( last.m ) && ( last.i += res[0].length, out += replacement );
out += str.substring( last.i, res.index );
last.i = res.index;
last.m = res[0];
}
}
/// Normal string support -- case sensitive
else {
while( (res = str.indexOf( needle, res+1 )) !== -1 ) {
( last.m ) && ( last.i += needle.length, out += replacement );
out += str.substring( last.i, res );
last.i = res;
last.m = needle;
}
}
return out + str.substring( last.i );
}
var str = replaceAllBarLast(
"How about a how about b how about c",
/how about\s*/gi,
''
);
console.log(str);
无论使用哪种语言,都没有内置方法可以做到这一点。你可以做的是(可能需要调试)
string customReplace(string original, string replaceThis, string withThis)
{
int last = original.lastIndexOf(replaceThis);
int index = s.indexOf(replaceThis);
while(index>=0 && index < last )
{
original = original.left(index)+ original.right(index+replaceThis.length);
last = original.lastIndexOf(replaceThis); // gotta do this since you changed the string
index = s.indexOf(replaceThis);
}
return original; // same name, different contents. In C# is valid.
}