{"id":2288,"date":"2021-02-09T12:52:54","date_gmt":"2021-02-09T03:52:54","guid":{"rendered":"http:\/\/141.164.34.82\/?p=2288"},"modified":"2021-02-15T04:27:19","modified_gmt":"2021-02-14T19:27:19","slug":"data-table-fillna","status":"publish","type":"post","link":"http:\/\/ds.sumeun.org\/?p=2288","title":{"rendered":"data.table fillna"},"content":{"rendered":"<h2>\ub370\uc774\ud130 \ud14c\uc774\ube14\uc5d0\uc11c \uacb0\uce21\uac12 \ucc44\uc6b0\uae30<\/h2>\n<p>\ub370\uc774\ud130 \ud14c\uc774\ube14\uc758 \ubb38\ubc95\uc740 \ub370\uc774\ud130 \ud504\ub808\uc784\uc758 \uadf8\uac83\uacfc \uc870\uae08 \ub2ec\ub77c\uc11c \ud65c\uc6a9\ud558\ub294\ub370 \uc560\ub97c \uba39\uc744 \uc218 \uc788\ub2e4.<\/p>\n<p>\ud558\uc9c0\ub9cc \ub370\uc774\ud130 \ud14c\uc774\ube14\uc740 \ub370\uc774\ud130 \ud504\ub808\uc784\uc73c\ub85c \ud560 \uc218 \uc788\ub294 \uac70\uc758 \ubaa8\ub4e0 \uac83\uc744 \uc9c0\uc6d0\ud558\uace0 \uc788\uc73c\uba70, \uac70\uae30\uc5d0 <strong>\uc81c\uc790\ub9ac \uc5f0\uc0b0(in-place operation)<\/strong>\uc744 \ucd94\uac00\ud55c\ub2e4\uace0 \uc0dd\uac01\ud558\uba74 \uc27d\ub2e4.<\/p>\n<p><strong>\uc81c\uc790\ub9ac \uc5f0\uc0b0(in-place operation)<\/strong>\uc774\ub780 \uceec\ub7fc\uc744 \uc218\uc815\ud560 \ub54c \uc0c8\ub85c\uc6b4 \ub370\uc774\ud130 \ud14c\uc774\ube0c\uc744 \uc0dd\uc131\ud558\ub294 \uac83\uc774 \uc544\ub2c8\ub77c \ubc14\ub85c \uadf8 \uc790\ub9ac\uc5d0\uc11c \uc218\uc815\ud558\ub294 \uac83\uc744 \uc758\ubbf8\ud55c\ub2e4. \ub2e4\uc74c\uc758 \uc608\ub97c \ubcf4\uc790.<\/p>\n<pre><code class=\"r\">library(data.table)\n\ndt0 = data.table(dt = c(as.Date(c(&#39;2021-01-01&#39;, NA, &#39;2030-03-01&#39;)), Sys.Date()),\n                 name = c(&#39;K&#39;, NA, &#39;P&#39;, &#39;J&#39;),\n                 ctr = c(NA, 1,3,2))\n\ndtA &lt;- copy(dt0)  # dtA &lt;- dt0 \uacfc \uacb0\uacfc\uac00 \ub2e4\ub984\uc744 \uc720\uc758\ud558\uc790.\ndtB &lt;- copy(dt0)\n\ndt0\n<\/code><\/pre>\n<pre>##            dt name ctr\n## 1: 2021-01-01    K  NA\n## 2:       &lt;NA&gt; &lt;NA&gt;   1\n## 3: 2030-03-01    P   3\n## 4: 2021-02-15    J   2\n<\/pre>\n<ul>\n<li>\ube44\uad50 : \uc81c\uc790\ub9ac \uc5f0\uc0b0<\/li>\n<\/ul>\n<pre><code class=\"r\">dtA[, name:=ifelse(is.na(name), &#39;unknown&#39;, name)]\ndtA\n<\/code><\/pre>\n<pre>##            dt    name ctr\n## 1: 2021-01-01       K  NA\n## 2:       &lt;NA&gt; unknown   1\n## 3: 2030-03-01       P   3\n## 4: 2021-02-15       J   2\n<\/pre>\n<ul>\n<li>\ube44\uad50 : \uc0c8\ub85c\uc6b4 \ub370\uc774\ud130\ud14c\uc774\ube14 \uc0dd\uc131<\/li>\n<\/ul>\n<pre><code class=\"r\">dtB[, .(name=ifelse(is.na(name), &#39;unknown&#39;, name))]\n<\/code><\/pre>\n<pre>##       name\n## 1:       K\n## 2: unknown\n## 3:       P\n## 4:       J\n<\/pre>\n<pre><code class=\"r\">dtB[, .(dt, name=ifelse(is.na(name), &#39;unknown&#39;, name), ctr)]\n<\/code><\/pre>\n<pre>##            dt    name ctr\n## 1: 2021-01-01       K  NA\n## 2:       &lt;NA&gt; unknown   1\n## 3: 2030-03-01       P   3\n## 4: 2021-02-15       J   2\n<\/pre>\n<pre><code class=\"r\">colns = names(dtB)\ncolns = colns[colns!=&#39;name&#39;]\ndtB[, c(.SD, .(name = ifelse(is.na(name), &#39;unknown&#39;, name))), .SDcols=colns]\n<\/code><\/pre>\n<pre>##            dt ctr    name\n## 1: 2021-01-01  NA       K\n## 2:       &lt;NA&gt;   1 unknown\n## 3: 2030-03-01   3       P\n## 4: 2021-02-15   2       J\n<\/pre>\n<h2>\uacb0\uce21\uce58 \uc81c\uac70<\/h2>\n<p>\uc6b0\uc120 \uacb0\uce21\uce58\ub97c \uc81c\uac70\ud558\ub294 \ud568\uc218\ub97c \ub9cc\ub4e4\uc5b4 \ub450\ub294\uac8c \uc88b\uaca0\ub2e4.<\/p>\n<pre><code class=\"r\">fillna = function(x) { \n  if (inherits(x, &quot;Date&quot;))\n    x[is.na(x)] = as.Date(&#39;0000-01-01&#39;)\n  else if (inherits(x, &#39;character&#39;)) {\n    x[is.na(x)] = &#39;&#39;\n  } else {\n    x[is.na(x)] = 0\n  }\n  x}\n<\/code><\/pre>\n<p>\uc704\uc758 \ud568\uc218 <code>fillna<\/code>\ub294 \ubca1\ud130 <code>x<\/code>\uac00 <code>Date<\/code> \ud074\ub798\uc2a4\uc77c \ub54c\ub294 NA\ub97c <code>0000-01-01<\/code>\ub85c, \ubb38\uc790\uc5f4\uc77c \ub54c\uc5d0\ub294 NA\ub97c <code>&#39;&#39;<\/code>\ub85c, \uadf8 \ubc16\uc5d0\ub294 <code>0<\/code>\uc73c\ub85c \ucc44\uc6b4\ub2e4.<\/p>\n<p>\uc774\ub807\uac8c NA\ub97c \ucc44\uc6b4 \uc0c8\ub85c\uc6b4 \ub370\uc774\ud130 \ud14c\uc774\ube14\uc740 \ub2e4\uc74c\uacfc \uac19\uc774&hellip;<\/p>\n<pre><code class=\"r\">dtA[, lapply(.SD, fillna)]\n<\/code><\/pre>\n<pre>##            dt    name ctr\n## 1: 2021-01-01       K   0\n## 2: 0000-01-01 unknown   1\n## 3: 2030-03-01       P   3\n## 4: 2021-02-15       J   2\n<\/pre>\n<p>\uae30\uc874\uc758 \ub370\uc774\ud130 \ud14c\uc774\ube14\uc5d0 \ub36e\uc5b4 \uc50c\uc6b4\ub2e4\uba74&hellip; (\uba54\ubaa8\ub9ac\uac00 \ubd80\uc871\ud560 \ub54c \uc720\uc6a9\ud558\ub2e4)<\/p>\n<pre><code class=\"r\">coln = names(dtA)\ndtA[, `:=`(c(coln), lapply(.SD, fillna)), .SDcols = coln]\n<\/code><\/pre>\n<p>\ub9cc\uc57d \uacb0\uce21\uce58\ub97c \uc81c\uac70\ud558\ub824\ub294 \uc218\uce58\ud615 \uceec\ub7fc\uc758 \uc774\ub984\uc744 \uc774\ubbf8 \uc54c\uace0 \uc788\ub2e4\uba74,<\/p>\n<pre><code class=\"r\">coln = &#39;ctr&#39;\ndtB[, lapply(.SD, fillna), .SDcols = coln]\n<\/code><\/pre>\n<pre>##    ctr\n## 1:   0\n## 2:   1\n## 3:   3\n## 4:   2\n<\/pre>\n<pre><code class=\"r\">cbind(dtB[, !..coln], dtB[, lapply(.SD, fillna), .SDcols = coln])\n<\/code><\/pre>\n<pre>##            dt name ctr\n## 1: 2021-01-01    K   0\n## 2:       &lt;NA&gt; &lt;NA&gt;   1\n## 3: 2030-03-01    P   3\n## 4: 2021-02-15    J   2\n<\/pre>\n<pre><code class=\"r\"># coln\uc81c\uc678\ud55c \ub370\uc774\ud130 \ud14c\uc774\ube14 = dtB[, !..coln]\n# coln\uc5d0\ub9cc fillna \ud568\uc218 \uc801\uc6a9\ud55c \uacb0\uacfc dtB[, lapply(.SD, fillna), .SDcols = coln]\n<\/code><\/pre>\n<p>\uc624, \uc774 \uad34\ub784\ud55c \ubb38\ubc95\uc774\uc5ec!<\/p>\n<h2>\uacb0\ub860<\/h2>\n<p><a href=\"http:\/\/141.164.34.82\/?p=2069\">R\ub85c \ud558\ub294 \ube45 \ub370\uc774\ud130 \ubd84\uc11d(\uac1c\uc815\ud310)<\/a>\uc5d0\ub294 \ub370\uc774\ud130 \ud504\ub808\uc784\uc73c\ub85c \ud560 \uc218 \uc788\ub294 \uc5ec\ub7ec \uc791\uc5c5\uc744 \uc190\uc27d\uac8c \ub370\uc774\ud130\ud14c\uc774\ube14\ub85c \uc218\ud589\ud560 \uc218 \uc788\ub3c4\ub85d \uad00\ub828 \ub0b4\uc6a9\ub4e4\uc744 \uccb4\uacc4\uc801\uc73c\ub85c \uc815\ub9ac\ud574 \ub193\uc558\ub2e4.<\/p>\n<p>\ub370\uc774\ud130 \ud14c\uc774\ube14\uc758 \ubb38\ubc95\uc744 \ubc30\uc6b0\uc9c0 \uc54a\uace0 \ub370\uc774\ud130 \ud14c\uc774\ube14\uc744 \uc0ac\uc6a9\ud558\uace0\uc790 \ud55c\ub2e4\uba74 <a href=\"https:\/\/github.com\/tidyverse\/dtplyr\"><code>dtplyr<\/code><\/a>\uc774\ub780 \ud328\ud0a4\uc9c0\uac00 \ub3c4\uc6c0\uc774 \ub420 \uac83\uc774\ub2e4.<\/p>\n<p>\ud558\uc9c0\ub9cc dtplyr\uc740 data.table\ubcf4\ub2e4 \uc870\uae08 \ub290\ub9ac\ub2e4\uace0 \ud55c\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\ub370\uc774\ud130 \ud14c\uc774\ube14\uc5d0\uc11c \uacb0\uce21\uac12 \ucc44\uc6b0\uae30 \ub370\uc774\ud130 \ud14c\uc774\ube14\uc758 \ubb38\ubc95\uc740 \ub370\uc774\ud130 \ud504\ub808\uc784\uc758 \uadf8\uac83\uacfc \uc870\uae08 \ub2ec\ub77c\uc11c \ud65c\uc6a9\ud558\ub294\ub370 \uc560\ub97c \uba39\uc744 \uc218 \uc788\ub2e4. \ud558\uc9c0\ub9cc \ub370\uc774\ud130 \ud14c\uc774\ube14\uc740 \ub370\uc774\ud130 \ud504\ub808\uc784\uc73c\ub85c \ud560 \uc218 \uc788\ub294 \uac70\uc758 \ubaa8\ub4e0 \uac83\uc744 \uc9c0\uc6d0\ud558\uace0 \uc788\uc73c\uba70, \uac70\uae30\uc5d0 \uc81c\uc790\ub9ac \uc5f0\uc0b0(in-place operation)\uc744 \ucd94\uac00\ud55c\ub2e4\uace0 \uc0dd\uac01\ud558\uba74 \uc27d\ub2e4. \uc81c\uc790\ub9ac \uc5f0\uc0b0(in-place operation)\uc774\ub780 \uceec\ub7fc\uc744 \uc218\uc815\ud560 \ub54c \uc0c8\ub85c\uc6b4 \ub370\uc774\ud130 \ud14c\uc774\ube0c\uc744 \uc0dd\uc131\ud558\ub294 \uac83\uc774 \uc544\ub2c8\ub77c \ubc14\ub85c \uadf8 \uc790\ub9ac\uc5d0\uc11c \uc218\uc815\ud558\ub294 \uac83\uc744 \uc758\ubbf8\ud55c\ub2e4. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2294,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[28,207],"tags":[479,478,182],"jetpack_featured_media_url":"http:\/\/ds.sumeun.org\/wp-content\/uploads\/2021\/02\/dt_fillna.png","_links":{"self":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts\/2288"}],"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=2288"}],"version-history":[{"count":6,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts\/2288\/revisions"}],"predecessor-version":[{"id":2296,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/posts\/2288\/revisions\/2296"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=\/wp\/v2\/media\/2294"}],"wp:attachment":[{"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2288"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2288"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/ds.sumeun.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2288"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}