替换两个单词之间的文字

Question

This question seems to be simple and repetitive here in SO.

But consider this string: SELECT a, b, c, d FROM . I want to get only what is between SELECT and FROM .

Nice so I have found this answer that propose this regex: (?<=SELECT)(.*)(?=FROM) . It's perfect if lookbehind works in JavaScript, according to this post :

Unlike lookaheads, JavaScript doesn't support regex lookbehind syntax

So it won't work(test it in regexpal that is made for JS). This anwser proposes this regex: SELECT=(.*?)FROM . But it includes the two words, so it not fits my needs.

The purpose of this is to use in a replace function to transform this...

SELECT a, b, c, d FROM

into this...

SELECT Count(*) FROM

Thank you in advance.

Answer 1

只需使用捕获组：

"SELECT a, b, c, d FROM".replace(/(SELECT)(.+?)(?= FROM)/, "$1 count(*)")

Answer 2

Try this:-

$("button").click(function() {
var srctext = $("#fixme").text();
console.log("old text: " + srctext);

var newtext = srctext.replace(/(SELECT)(.+?)(?= FROM)/, "$1 count(*)");
console.log("new text: " + newtext);

$("#fixme").text(newtext)
});

WORKING JSFIDDLE:- http://jsfiddle.net/tkP74/1597/

Answer 3

好吧，你可以像我在评论中所说的那样把SELECT放回去：

str.replace(/SELECT (.*?)(?= FROM)/i, "SELECT Count(*)");

Answer 4

正如此特定字符串的正则表达式的替代方法：

str = 'SELECT COUNT(*) ' + str.substr(str.indexOf('FROM'));

Answer 5

Without regex :

var query = "SELECT a, b, c, d FROM";
var iSelect = query.indexOf("SELECT");
var selLen = "SELECT".length;
var iFrom = query.indexOf("FROM");
if (iSelect >= 0 && iFrom >= 0) {
    query = query.replace(query.substring(iSelect + selLen, iFrom), " COUNT(*) ");
    console.log(query);
}