json - Extract only first match with Regex in Scala -



json - Extract only first match with Regex in Scala -

i'm trying extract specific string value json-formatted string in scala. however, going used in production environment, i'm concerned efficiency. currently, i'm using bit of code below:

val r = """identifier=\{s: ([\w\.]+),""".r var identifier: string = ""; r.findallin(queryresult tostring).matchdata foreach { m => identifier = m.group(1) }

my concern efficiency. don't need validate json (that's beingness produced aws, i'm assuming it's good, , if it's not, can't alter it), there's no reason go through overhead of parsing out.

that said, can more efficiently regex, or have go downwards level of finding first occurence of 'identifier={s: ', next occurence of ',' after that, , substring between two? trying r.findfirstin can't figure out way extract grouping want that.

or there other super efficient thing i'm not aware of doing?

regex json scala share|improve question asked oct 30 '14 @ 18:24 childofsoong 1,312519 5   since in production environment, utilize json parser please. – nhahtdh oct 30 '14 @ 18:25 2   better utilize well-established parser seek parsing via regex. premature optimization < completeness – m-z oct 30 '14 @ 18:31      how big json string ? identifier=somestring seem string value within json. lot clearer if can share sample json dealing with. – tuxdna oct 30 '14 @ 18:38      the json string quite large, hence why didn't want overhead of parsing entire thing. , when 'production', don't mean stuff goes on consumers - mean we're using test our server interacts db. – childofsoong oct 30 '14 @ 19:50      @nhahtdh should mention don't know if normal json parser parse content response aws dynamodb. formal json specification says string should written "content" s: content – childofsoong oct 30 '14 @ 20:06 add comment |  1 reply 1 active oldest votes up vote 0 down vote accepted

you want first match:

r.findfirstmatchin(queryresult.tostring).map(_.group(1))

(will option[string].)

that said, i'd utilize streaming json parser every time on regex. yes, regex faster, unless really bottleneck, more worried accuracy.

share|improve answer answered oct 30 '14 @ 20:15 rex kerr 120k15216328      neater utilize r.unanchored, s match { case ru(g) => }. click triangle at: scala-lang.org/files/archive/nightly/2.11.x/api/2.11.x/… – som-snytt oct 31 '14 @ 4:54 add comment |  your answer stackexchange.ifusing("editor", function () { stackexchange.using("externaleditor", function () { stackexchange.using("snippets", function () { stackexchange.snippets.init(); }); }); }, "code-snippets"); stackexchange.ready(function() { inittagrenderer("".split(" "), "".split(" ")); stackexchange.using("externaleditor", function() { // have fire editor after snippets, if snippets enabled if (stackexchange.options.snippets.enabled) { stackexchange.using("snippets", function() { createeditor(); }); } else { createeditor(); } }); function createeditor() { prepareeditor({ heartbeattype: 'answer', convertimagestolinks: true, reputationtopostimages: 10, bindnavprevention: true, postfix: "", ondemand: true, discardselector: ".discard-answer" ,immediatelyshowmarkdownhelp:true }); } });   draft saved draft discarded sign or log in stackexchange.ready(function () { stackexchange.helpers.onclickdraftsave('#login-link'); });

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