{"id":10607,"date":"2020-11-11T11:16:59","date_gmt":"2020-11-11T02:16:59","guid":{"rendered":"http:\/\/www.gisdeveloper.co.kr\/?p=10607"},"modified":"2020-11-11T11:17:19","modified_gmt":"2020-11-11T02:17:19","slug":"kotlin-%ea%b3%a0%ec%9c%a0%ec%9d%98-%ed%91%9c%ec%a4%80%ed%95%a8%ec%88%98-let-also-apply-with-run","status":"publish","type":"post","link":"http:\/\/www.gisdeveloper.co.kr\/?p=10607","title":{"rendered":"Kotlin \uace0\uc720\uc758 \ud45c\uc900\ud568\uc218 (let, also, apply, with, run, …)"},"content":{"rendered":"

\ub2e4\uc2dc \uace0\ub4f1\ud559\uc0dd\uc774 \ub41c \uae30\ubd84\uc785\ub2c8\ub2e4. let, also, with \ub4f1 \ub9e4\uc6b0 \uae30\ucd08\uc801\uc778 \uc601\uc5b4 \ub2e8\uc5b4\ub97c \uc678\uc6b0\ub294 \uae30\ubd84\uc778\ub370\uc694. \uc6d0\ub798\ub294 \ud45c\uc900\ud568\uc218\ub85c \ubd88\ub9ac\uc9c0\ub9cc Kotlin\uc5d0\uc11c \uace0\uc720\ud558\uac8c \uc81c\uacf5\ud558\ubbc0\ub85c \uace0\uc720\uc758 \ud45c\uc900\ud568\uc218\ub77c\ub294 \uc81c\ubaa9\uc744 \ubd99\uc600\uc2b5\ub2c8\ub2e4. \uc774 \ud568\uc218\ub4e4\uc744 \uc0ac\uc6a9\ud558\uc5ec \ucf54\ub4dc\ub97c \uc880\ub354 \ucd5c\uc801\ud654 \uc2dc\ucf1c\uc904 \uc218 \uc788\uc73c\uba70 \ubd88\ud544\uc694\ud55c \ucf54\ub529\ub7c9\uc744 \uc904\uc77c \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n

let<\/h3>\n

\uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n

\r\ndata class WHAT(val name: String, val age: Int)\r\n\r\nfun main() {\r\n    println(\"Case 1\")\r\n\r\n    var w: WHAT? = null\r\n\r\n    val v = w?.let {\r\n        println(it)\r\n    } ?: \"Known\"\r\n\r\n    println(v)\r\n\r\n    println(\"Case 2\")\r\n\r\n    var W: WHAT? = WHAT(\"Dip2K\", 43)\r\n\r\n    val V = W?.let {\r\n        println(it)\r\n    } ?: \"Known\"\r\n\r\n    println(V)\r\n}\r\n<\/pre>\n
\uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\ub2e4.<\/p>\n
\r\nCase 1\r\nKnown\r\nCase 2\r\nWHAT(name=Dip2K, age=43)\r\nkotlin.Unit\r\n<\/pre>\n
let\uc740 \ubc1b\uc740 \uac1d\uccb4(w)\ub97c \ub78c\ub2e4 \ud568\uc218 \ub0b4\ubd80\uc5d0\uc11c it\uc73c\ub85c \ubc1b\uc544 \uc0ac\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ubc18\ud658\uac12\uc740 \ub78c\ub2e4 \ud568\uc218\uc758 \uac00\uc7a5 \ub9c8\uc9c0\ub9c9 \ucf54\ub4dc\uc758 \ubc18\ud658\uac12\uc774 \ub429\ub2c8\ub2e4.<\/p>\n
also<\/h3>\n
\uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\ndata class WHAT(val name: String, val age: Int)\r\n\r\nfun main() {\r\n    println(\"Case 1\")\r\n\r\n    var w: WHAT? = null\r\n\r\n    val v = w?.also {\r\n        println(it)\r\n    } ?: \"Known\"\r\n\r\n    println(v)\r\n\r\n    println(\"Case 2\")\r\n\r\n    var W: WHAT? = WHAT(\"Dip2K\", 43)\r\n\r\n    val V = W?.also {\r\n        println(it)\r\n    } ?: \"Known\"\r\n\r\n    println(V)\r\n}\r\n<\/pre>\n
\uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\ub2e4.<\/p>\n
\r\nCase 1\r\nKnown\r\nCase 2\r\nWHAT(name=Dip2K, age=43)\r\nWHAT(name=Dip2K, age=43)\r\n<\/pre>\n
also \ud568\uc218\ub294 \ubc1b\uc740 \uac1d\uccb4\ub97c it\uc73c\ub85c \ubc1b\uc544 \uc0ac\uc6a9\ud560 \uc218 \uc788\uc73c\uba70, \ubc1b\uc740 \uac1d\uccb4\ub97c \uadf8\ub300\ub85c \uadf8\ub300\ub85c \ubc18\ud658\ud569\ub2c8\ub2e4.<\/p>\n
apply<\/h3>\n
\uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\ndata class WHAT(var name: String, var age: Int)\r\n\r\nfun main() {\r\n    val w = WHAT(\"Jackass\", 16)\r\n\r\n    val r = w.apply {\r\n        name = \"Dip2K\"\r\n        age = 43\r\n    }\r\n\r\n    println(w)\r\n    println(r)\r\n}\r\n<\/pre>\n
\uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\ub2e4.<\/p>\n
\r\nWHAT(name=Dip2K, age=43)\r\nWHAT(name=Dip2K, age=43)\r\n<\/pre>\n
apply\ub294 \ubc1b\uc740 \uac1d\uccb4\ub97c \ub78c\ub2e4 \ud568\uc218 \ub0b4\ubd80\uc5d0\uc11c it\uc774 \uc544\ub2cc this\ub85c \ucc98\ub9ac\ud569\ub2c8\ub2e4. \ubc1b\uc740 \uac1d\uccb4\ub97c \uadf8\ub300\ub85c \ubc18\ud658\ud569\ub2c8\ub2e4.<\/p>\n
with<\/h3>\n
\uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\npackage with\r\n\r\ndata class WHAT(var name: String, var age: Int)\r\n\r\nfun main() {\r\n    val w = WHAT(\"Jackass\", 16)\r\n\r\n    val r = w?.let {\r\n        with(it) {\r\n            name = \"Dip2K\"\r\n            age = 43\r\n            \"Good day!\"\r\n        }\r\n    }\r\n\r\n    println(w)\r\n    println(r)\r\n}\r\n<\/pre>\n
\uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\ub2e4.<\/p>\n
\r\nWHAT(name=Dip2K, age=43)\r\nGood day!\r\n<\/pre>\n
with \ud568\uc218\ub294 \uc778\uc790\ub85c \ubc1b\uc740 \uac1d\uccb4\ub97c \ub78c\ub2e4 \ud568\uc218 \uc548\uc5d0\uc11c this\ub85c \uc0ac\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ubc18\ud658\uac12\uc740 \ub78c\ub2e4 \ud568\uc218\ub97c \uad6c\uc131\ud558\ub294 \uac00\uc7a5 \ub9c8\uc9c0\ub9c9 \ucf54\ub4dc\uc785\ub2c8\ub2e4.<\/p>\n
run<\/h3>\n
\uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\ndata class WHAT(var name: String, var age: Int)\r\n\r\nfun main() {\r\n    val v = run {\r\n        val w = WHAT(\"Jackass\", 16)\r\n        w\r\n    }\r\n\r\n    println(v)\r\n\r\n    val vv = v.run {\r\n        name = \"Dip2K\"\r\n        age = 43\r\n\r\n        \"Good day !\"\r\n    }\r\n\r\n    println(v)\r\n    println(vv)\r\n}\r\n<\/pre>\n
\uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\ub2e4.<\/p>\n
\r\nWHAT(name=Jackass, age=16)\r\nWHAT(name=Dip2K, age=43)\r\nGood day !\r\n<\/pre>\n
run\uc740 \uac1d\uccb4\ub97c \uc804\ub2ec\ubc1b\uc9c0 \uc54a\uace0 \ub3c5\ub9bd\uc801\uc73c\ub85c \uc2e4\ud589\ud558\ub294 \uacbd\uc6b0\uc640 \uac1c\uccb4\ub97c \uc804\ub2ec\ubc1b\uc544 \ucc98\ub9ac\ud558\ub294 \uacbd\uc6b0\ub85c \uad6c\ubd84\ub429\ub2c8\ub2e4. \uac1d\uccb4\ub97c \uc804\ub2ec\ubc1b\uc544 \ucc98\ub9ac\ud558\ub294 \uacbd\uc6b0 \uc804\ub2ec\ubc1b\uc740 \uac1d\uccb4\ub97c \ub78c\ub2e4 \ud568\uc218 \ub0b4\ubd80\uc5d0\uc11c this\ub85c \ubc1b\uc544 \uc0ac\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ubc18\ud658\uac12\uc740 \ub78c\ub2e4 \ud568\uc218\uc758 \ub9c8\uc9c0\ub9c9 \ucf54\ub4dc\uc785\ub2c8\ub2e4. <\/p>\n
use<\/h3>\n
\uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\nimport java.io.File\r\n\r\nfun main() {\r\n    val f = File(\"d:\/a.txt\")\r\n    f.bufferedWriter().use {\r\n        it.appendln(\"Hello, GIS Developer.\")\r\n        it.append(\"Good Day !\")\r\n    }\r\n}\r\n<\/pre>\n
use \ud568\uc218\ub294 \uc804\ub2ec \ubc1b\uc740 \uac1d\uccb4\ub97c it\uc73c\ub85c \ub78c\ub2e4 \ud568\uc218 \ub0b4\ubd80\uc5d0\uc11c \uc0ac\uc6a9\ud558\uba70, \ub78c\ub2e4 \ud568\uc218 \uc885\ub8cc\uc2dc close \ud568\uc218\ub97c \uc790\ub3d9\uc73c\ub85c \ud638\ucd9c\ud574 \uc90d\ub2c8\ub2e4.<\/p>\n
takeIf, takeUnless<\/h3>\n
\uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\ndata class WHAT(var name: String, var age: Int)\r\n\r\nfun main() {\r\n    val w = WHAT(\"Jackass\", 16)\r\n\r\n    val v = w?.takeIf { it.age < 20 }\r\n    \/\/val v = w?.takeUnless { it.age >= 20 } <- \uc704\uc758 \ucf54\ub4dc\uc640 \ub3d9\uc77c\ud568\r\n    println(v)\r\n\r\n    var r = v?.apply {\r\n        name = \"Dip2K\"\r\n    }\r\n    println(r)\r\n}\r\n<\/pre>\n
\uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\ub2e4.<\/p>\n
\r\nWHAT(name=Jackass, age=16)\r\nWHAT(name=Dip2K, age=16)\r\n<\/pre>\n
takeIf \ud568\uc218\ub294 \ubc1b\uc740 \uac1d\uccb4\ub97c \ub78c\ub2e4 \ud568\uc218 \ub0b4\ubd80\uc5d0\uc11c it\uc73c\ub85c \ucc98\ub9ac\ud558\uba70, \ubc18\ud658\uac12\uc774 true\uc77c\ub54c \ubc1b\uc740 \uac1d\uccb4\ub97c \ubc18\ud658\ud558\uace0, false\uc77c\ub54c null\uc744 \ubc18\ud658\ud569\ub2c8\ub2e4.<\/p>\n
measureTimeMillis<\/h3>\n
\uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\nimport kotlin.system.measureTimeMillis\r\n\r\nfun main() {\r\n    val time = measureTimeMillis {\r\n        Thread.sleep(10000)\r\n    }\r\n\r\n    println(time)\r\n}\r\n<\/pre>\n
\uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\ub2e4.<\/p>\n
\r\n10000\r\n<\/pre>\n
measureTimeMillis\uc740 \uc5b4\ub5a4 \ucf54\ub4dc\ub97c \uc2e4\ud589\ud558\ub294\ub370 \uc18c\uc694\ub418\ub294 \uc2dc\uac04\uc744 \uce21\uc815\ud558\ub294\ub370 \uc0ac\uc6a9\ub429\ub2c8\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"
\ub2e4\uc2dc \uace0\ub4f1\ud559\uc0dd\uc774 \ub41c \uae30\ubd84\uc785\ub2c8\ub2e4. let, also, with \ub4f1 \ub9e4\uc6b0 \uae30\ucd08\uc801\uc778 \uc601\uc5b4 \ub2e8\uc5b4\ub97c \uc678\uc6b0\ub294 \uae30\ubd84\uc778\ub370\uc694. \uc6d0\ub798\ub294 \ud45c\uc900\ud568\uc218\ub85c \ubd88\ub9ac\uc9c0\ub9cc Kotlin\uc5d0\uc11c \uace0\uc720\ud558\uac8c \uc81c\uacf5\ud558\ubbc0\ub85c \uace0\uc720\uc758 \ud45c\uc900\ud568\uc218\ub77c\ub294 \uc81c\ubaa9\uc744 \ubd99\uc600\uc2b5\ub2c8\ub2e4. \uc774 \ud568\uc218\ub4e4\uc744 \uc0ac\uc6a9\ud558\uc5ec \ucf54\ub4dc\ub97c \uc880\ub354 \ucd5c\uc801\ud654 \uc2dc\ucf1c\uc904 \uc218 \uc788\uc73c\uba70 \ubd88\ud544\uc694\ud55c \ucf54\ub529\ub7c9\uc744 \uc904\uc77c \uc218 \uc788\uc2b5\ub2c8\ub2e4. let \uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4. data class WHAT(val name: String, val age: Int) fun main() { println(“Case … <\/p>\n
\ub354 \ubcf4\uae30 “Kotlin \uace0\uc720\uc758 \ud45c\uc900\ud568\uc218 (let, also, apply, with, run, …)”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[136],"tags":[],"class_list":["post-10607","post","type-post","status-publish","format-standard","hentry","category-kotlin"],"_links":{"self":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/10607","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10607"}],"version-history":[{"count":4,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/10607\/revisions"}],"predecessor-version":[{"id":10611,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/10607\/revisions\/10611"}],"wp:attachment":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10607"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10607"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10607"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}