{"id":1203,"date":"2019-05-12T05:40:12","date_gmt":"2019-05-11T20:40:12","guid":{"rendered":"http:\/\/141.164.34.82\/?p=1203"},"modified":"2019-05-12T06:02:23","modified_gmt":"2019-05-11T21:02:23","slug":"%ed%95%a8%ec%88%98%ec%9d%98-%ec%9d%b8%ec%9e%90%eb%a1%9c-%ed%95%a8%ec%88%98-%ec%93%b0%ea%b8%b0","status":"publish","type":"post","link":"http:\/\/ds.sumeun.org\/?p=1203","title":{"rendered":"\ud568\uc218\uc758 \uc778\uc790\ub85c \ud568\uc218 \uc4f0\uae30"},"content":{"rendered":"<h1>\ud568\uc218\ud615 \ud504\ub85c\uadf8\ub798\ubc0d<\/h1>\n<p>\ud568\uc218\ud615 \ud504\ub85c\uadf8\ub798\ubc0d \uc5b8\uc5b4\uc5d0\uc11c\ub294 <strong>\ud568\uc218<\/strong>\ub97c <strong>\ud568\uc218\uc758 \uc778\uc790<\/strong>\ub85c \uc4f8 \uc218 \uc788\ub2e4.<\/p>\n<p>\ubaa8\ub450 \ud568\uc218\uac00 \ubb34\uc5c7\uc778\uc9c0\ub294 \uc54c \uac83\uc774\ub2e4.<\/p>\n<pre><code class=\"r\">f = function(x,y) {\r\n  return(x^y)\r\n}\r\n\r\nf(3,2)\r\n<\/code><\/pre>\n<pre>## [1] 9\r\n<\/pre>\n<h2>\ud568\uc218\ub97c \ud568\uc218\uc758 \uc778\uc790\ub85c<\/h2>\n<p><strong>\ud568\uc218<\/strong>\ub97c \uc778\uc790\ub85c \ubc1b\uc544\uc11c \uc0c8\ub85c\uc6b4 \ud568\uc218\ub97c \ub9cc\ub4dc\ub294 \uc608\ub97c \ub4e4\uc5b4\ubcf4\uc790.<\/p>\n<pre><code class=\"r\">g = function(f,z) {\r\n  return(function(x,y) f(x,y)^z)\r\n}\r\n\r\nh=g(f,2)\r\nh(3,2)\r\n## [1] 81\r\n(3^2)^2\r\n## [1] 81\r\nh(3,2) == (3^2)^2\r\n## [1] TRUE\r\n<\/code><\/pre>\n<p>\ud568\uc218 <code>g<\/code>\ub294 \ud568\uc218 <code>f<\/code>\ub97c \uc778\uc790\ub85c \ubc1b\uc544\uc11c \uc0c8\ub85c\uc6b4 \ud568\uc218\ub97c \ubc18\ud658\ud55c\ub2e4. \uc0c8\ub85c\uc6b4 \ud568\uc218\uc758 \uc778\uc790\ub294 <code>x<\/code>, <code>y<\/code>\uc774\uace0, \ubc18\ud658\uac12\uc740 <code>f(x,y)^z<\/code>\uac00 \ub41c\ub2e4. \uc704\uc758 \ucf54\ub4dc\ub97c \uc2e4\ud589\uc2dc\ud0a4\uba74 <code>h<\/code>\uc5d0\ub294 <code>g(f,2)<\/code>, \ub2e4\uc2dc \ub9d0\ud574, \uc785\ub825\uc73c\ub85c <code>x<\/code>, <code>y<\/code>\ub97c \ubc1b\uc73c\uba74, <code>f(x,y)^2<\/code>\ub97c \ubc18\ud658\ud558\ub294 \ud568\uc218\uac00 \ub2f4\uae30\uac8c \ub41c\ub2e4. <code>f(x,y)<\/code>\ub294 <code>x^y<\/code>\uc774\ubbc0\ub85c, <code>f(x,y)^z<\/code>\uc740 <code>(x^y)^2<\/code>\uac00 \ubc18\ud658\ub41c\ub2e4.<\/p>\n<h3>\uc778\uc790 \ud568\uc218(\uc6d0\ub798 \ud568\uc218)\uc758 \uc778\uc790<\/h3>\n<p>\ud568\uc218\ub97c \uc778\uc790\ub85c \uc8fc\uace0 \ubc1b\uc744 \ub54c \ubb38\uc81c\uc758 \ud558\ub098\ub294 \ud568\uc218\uc758 \uc778\uc790\ub97c \ucc98\ub9ac\ud558\ub294 \uac83\uc774\ub2e4.<\/p>\n<p>\uc608\ub97c \ub4e4\uc5b4 <code>apply()<\/code>\ud568\uc218\ub97c \ubcf4\uc790. <code>apply(mat, 1, sum)<\/code>\uc740 \ud589\ub82c <code>mat<\/code>\uc758 \ud589\ubcc4\ub85c \ud569\uc0b0(<code>sum()<\/code>)\uc744 \ud55c\ub2e4. \uadf8\ub7f0\ub370 \ud569\uc0b0 \ud568\uc218 <code>sum()<\/code>\uc758 \uc5ec\ub7ec \uc635\uc158\uc744 \ubcc0\uacbd\ud558\ub824\uba74 \uc5b4\ub5bb\uac8c \ud574\uc57c \ud560\uae4c? \uc608\ub97c \ub4e4\uc5b4 <code>na.rm=TRUE<\/code>\ub85c \ubcc0\uacbd\ud558\uace0\uc790 \ud55c\ub2e4\uba74?<\/p>\n<pre><code class=\"r\">mat = matrix(c( 1,-3, 2,\r\n               -5, 3, 2,\r\n                1,-1,NA,\r\n               -3, 1, 2), 4,3, byrow=TRUE)\r\n\r\napply(X=mat, MARGIN=1, FUN=sum)\r\n<\/code><\/pre>\n<pre>## [1]  0  0 NA  0\r\n<\/pre>\n<pre><code class=\"r\">apply(mat, 1, sum)\r\n<\/code><\/pre>\n<pre>## [1]  0  0 NA  0\r\n<\/pre>\n<p>\ud568\uc218\ub97c \uc778\uc790\ub85c \ubc1b\ub294 R\uc758 \ud568\uc218\ub4e4\uc740 \ub300\ubd80\ubd84 \uc6d0\ub798 \ud568\uc218\uc758 \ub098\uba38\uc9c0 \uc778\uc790 \uc5ed\uc2dc \uc778\uc790\ub85c \ub118\uaca8 \uc904 \uc218 \uc788\ub2e4. \uc608\ub97c \ubcf4\uc790. \ub9cc\uc57d \uc704\uc758 \ucf54\ub4dc\uc5d0\uc11c \uac01 \ud589\ubcc4\ub85c <code>sum(x, na.rm=T)<\/code>\ub97c \ud558\uace0 \uc2f6\ub2e4\uba74, \ub2e4\uc74c\uacfc \uac19\uc774 \uc4f8 \uc218 \uc788\ub2e4.<\/p>\n<pre><code class=\"r\">apply(mat, 1, sum, na.rm=TRUE)\r\n<\/code><\/pre>\n<pre>## [1] 0 0 0 0\r\n<\/pre>\n<p>\ub9cc\uc57d \ud568\uc218 <code>apply<\/code>\uc758 \uc778\uc790\uc640 \ud568\uc218 <code>sum<\/code>\uc758 \ub9e4\uac1c\ubcc0\uc218\uc774\ub984\uc774 \uacb9\uce58\uc9c0 \uc54a\ub294\ub2e4\uba74, \ud568\uc218 <code>sum()<\/code>\uc758 \ubaa8\ub4e0 \uc778\uc790\ub97c \uc131\uacf5\uc801\uc73c\ub85c <code>apply()<\/code>\uc5d0 \ub118\uaca8 \uc904 \uc218 \uc788\uc74c\uc744 \uc8fc\ubaa9\ud558\uc790. (\uc544\ub9c8\ub3c4 \ud568\uc218 <code>apply(X=, MARGIN=, FUN=)<\/code>\uc758 \ub9e4\uac1c\ubcc0\uc218 \uc774\ub984\uc774 <code>X<\/code>, <code>MARGIN<\/code>, <code>FUN<\/code>\uacfc \uac19\uc774 \ub300\ubb38\uc790\uc778 \uc774\uc720\ub3c4 \uc6d0\ub798 \ud568\uc218\uc640 \ub9e4\uac1c\ubcc0\uc218 \uc774\ub984\uacfc \uacb9\uce58\uc9c0 \uc54a\uac8c \ud558\ub824\ub294 \uc758\ubbf8\uc600\uc744 \uac83 \uac19\ub2e4.[<sup>1])<\/sup><\/p>\n<p>[<sup>1]:<\/sup> \ud568\uc218 <code>f=function(x) x^2; f(x=3)<\/code>\uc744 \uc0dd\uac01\ud560 \ub54c <code>3<\/code>\uc740 \uc778\uc790(\ud568\uc218\uc5d0 \uc785\ub825\ub418\ub294 \uac12), \uadf8\ub9ac\uace0 <code>x<\/code>\ub294 \ub9e4\uac1c\ubcc0\uc218\ub77c\uace0 \ud560 \uc218 \uc788\ub2e4. \ub9e4\uac1c\ubcc0\uc218\ub780 \ub2e4\uc2dc \ub9d0\ud574 \ud568\uc218\uc5d0 \uc785\ub825\ub418\ub294 \uac12\uc774 \uc800\uc7a5\ub418\ub294 \ubcc0\uc218\ub77c\uace0 \uc774\ud574\ud558\uba74 \ub41c\ub2e4.<\/p>\n<h3>\uc778\uc790 \ud568\uc218(\uc6d0\ub798 \ud568\uc218)\uc758 \uc778\uc790\ub97c \uc0c8\ub85c\uc6b4 \ud568\uc218\uc758 \uc778\uc790\ub85c \ubc1b\uae30<\/h3>\n<p>\ud568\uc218\ub97c \uc778\uc790\ub85c \ubc1b\ub294 \ud568\uc218\uc5d0\uc11c \uc6d0\ub798 \ud568\uc218\uc758 \uc778\uc790\ub97c \ucc98\ub9ac\ud558\uae30 \uc704\ud574 <code>...<\/code>\ub97c \uc4f8 \uc218 \uc788\ub2e4(<code>...<\/code>\ub294 \uc601\uc5b4\ub85c dot-dot-dot\uc774\ub77c\uace0 \ud558\ub358\ub370, \uc6b0\ub9ac\ub098\ub77c\ub9d0\ub85c \uc9c1\uc5ed\ud558\uba74 \uc810\uc810\uc810 \ucbe4 \ub418\ub824\ub098?). \ud2b9\ud788 \uc6d0\ub798 \ud568\uc218\uc758 \uc778\uc790(\ub9e4\uac1c\ubcc0\uc218) \uc774\ub984\uc774 \ubb34\uc5c7\uc774\uace0, \uc778\uc790\uc758 \uac2f\uc218\uac00 \uba87 \uac1c\uc778\uc9c0 \uac00\ub2a0\ud560 \uc218 \uc5c6\uc744 \ub54c \uc694\uae34\ud558\ub2e4. \uc608\ub97c \ub4e4\uc5b4 \ubaa8\ub4e0 \uc778\uc790\uc758 \uc6d0\uc18c\ub97c \ud569\ud558\ub294 \ud569\uacc4 \ud568\uc218\ub97c \uc9c1\uc811 \ub9cc\ub4e4\uc5b4 \ubcf4\uc790.<\/p>\n<pre><code class=\"r\">sum2 = function(...) { sum(sapply(list(...), sum)) }\r\nsum2(c(1,3,2), c(4,2,2,1), c(-1,1,1,0,1))\r\n<\/code><\/pre>\n<pre>## [1] 17\r\n<\/pre>\n<pre><code class=\"r\">sum2(c(1,3,2), c(4,2,2,NA), c(-1,1,1,0,1))\r\n<\/code><\/pre>\n<pre>## [1] NA\r\n<\/pre>\n<p><code>list(...)<\/code>\uc740 \ubaa8\ub4e0 \uc778\uc790\ub97c \ub9ac\uc2a4\ud2b8\ub85c \ubc18\ud658\ud55c\ub2e4. \ud568\uc218 <code>sum2()<\/code>\ub294 \uadf8 \ub9ac\uc2a4\ud2b8\uc758 \ubaa8\ub4e0 \uc6d0\uc18c\uc5d0 \ub300\ud574 \ud569\uc744 \ud558\uace0, \uadf8 \ud569\uc5d0 \ub2e4\uc2dc \ud569\uc744 \ud55c\ub2e4. \uc5ec\uae30\uc11c <code>na.rm=<\/code>\uacfc \uac19\uc740 <code>sum()<\/code>\uc758 \ub9e4\uac1c\ubcc0\uc218\uc640 \uc778\uc790\ub97c \ubc1b\uace0 \uc2f6\ub2e4\uba74, \ub2e4\uc74c\uacfc \uac19\uc774 \ud560 \uc218 \uc788\ub2e4.<\/p>\n<pre><code class=\"r\">sum3 = function(..., na.rm=FALSE) {\r\n  sum(sapply(X=list(...), FUN=sum, na.rm=na.rm), na.rm=na.rm)\r\n}\r\n\r\nsum3(c(1,3,2), c(4,2,2,1), c(-1,1,1,0,1))\r\n<\/code><\/pre>\n<pre>## [1] 17\r\n<\/pre>\n<pre><code class=\"r\">sum3(c(1,3,2), c(4,2,2,NA), c(-1,1,1,0,1))\r\n<\/code><\/pre>\n<pre>## [1] NA\r\n<\/pre>\n<pre><code class=\"r\">sum3(c(1,3,2), c(4,2,2,NA), c(-1,1,1,0,1), na.rm=TRUE)\r\n<\/code><\/pre>\n<pre>## [1] 16\r\n<\/pre>\n<p><code>na.rm=na.rm<\/code>\uc5d0\uc11c <code>na.rm=<\/code>\ub294 <code>sum()<\/code>\uc758 \ub9e4\uac1c\ubcc0\uc218\uc774\ub984\uc744 \ub098\ud0c0\ub0b8\ub2e4. \ub4a4\uc774\uc5b4 \ub098\uc624\ub294 <code>na.rm<\/code>\ub294 <code>sum3()<\/code>\uc758 \uc778\uc790\ub85c \ubc1b\uc740 \uac12\uc744 \ub098\ud0c0\ub0b8\ub2e4.<\/p>\n<h3>\ud55c \uc904 \uc694\uc57d<\/h3>\n<p>R\uc5d0\uc11c \uc778\uc790 \ud568\uc218\uc758 \ubd88\ud2b9\uc815 \ub2e4\uc218\uc758 \uc778\uc790\ub97c \ucc98\ub9ac\ud558\uae30 \uc704\ud574 <code>...<\/code>(dot-dot-dot, \uc810\uc810\uc810)\uc744 \ud65c\uc6a9\ud560 \uc218 \uc788\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\ud568\uc218\ud615 \ud504\ub85c\uadf8\ub798\ubc0d \ud568\uc218\ud615 \ud504\ub85c\uadf8\ub798\ubc0d \uc5b8\uc5b4\uc5d0\uc11c\ub294 \ud568\uc218\ub97c \ud568\uc218\uc758 \uc778\uc790\ub85c \uc4f8 \uc218 \uc788\ub2e4. \ubaa8\ub450 \ud568\uc218\uac00 \ubb34\uc5c7\uc778\uc9c0\ub294 \uc54c \uac83\uc774\ub2e4. f = function(x,y) { return(x^y) } f(3,2) ## [1] 9 \ud568\uc218\ub97c \ud568\uc218\uc758 \uc778\uc790\ub85c \ud568\uc218\ub97c \uc778\uc790\ub85c \ubc1b\uc544\uc11c \uc0c8\ub85c\uc6b4 \ud568\uc218\ub97c \ub9cc\ub4dc\ub294 \uc608\ub97c \ub4e4\uc5b4\ubcf4\uc790. g = function(f,z) { return(function(x,y) f(x,y)^z) } h=g(f,2) h(3,2) ## [1] 81 (3^2)^2 ## [1] 81 h(3,2) == [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":1209,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[28,133],"tags":[276,278,280,277,279],"jetpack_featured_media_url":"http:\/\/ds.sumeun.org\/wp-content\/uploads\/2019\/05\/dotdotdot.png","_links":{"self":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts\/1203"}],"collection":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1203"}],"version-history":[{"count":6,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts\/1203\/revisions"}],"predecessor-version":[{"id":1210,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts\/1203\/revisions\/1210"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/media\/1209"}],"wp:attachment":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1203"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1203"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1203"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}