Javascript：如何从多行字符串中解析出一行？

Question

Currently I have a big string paragraph displayed using <pre> like the following where each line is represented using new line:

SchoolDistrictCode:291238-9
location_version:3.4
build:e9kem

From this, how can I parse just the build:e9kem out? The data varies every time, so once it recognizes the word build , would like to parse just that line.

Answer 1

/^build:(.*)$/m

should do the trick. The m flag will cause the ^ and $ anchors to match at the beginning and end of the line.

If you call this as

string.match(regexp)

The matching part (after the build: , the part matching .* , which is the string e9kem ) will be in the second element of the resulting array.

 const regexp = /^build:(.*)$/m; const stringPar = `SchoolDistrictCode:291238-9 location_version:3.4 build:e9kem`; console.log(stringPar.match(regexp)[1]);

Of course, match returns null if there are no matches, so you may want to check that:

var matches = stringPar.match(regexp);
if (matches) console.log(matches[1]);
else console.log("No match.");

Or, another common idiom is

console.log((stringPar.match(regexp) || [])[1]);

which will log undefined if there is not match.