{"id":3081,"date":"2015-07-08T10:54:13","date_gmt":"2015-07-08T09:54:13","guid":{"rendered":"https:\/\/abcdr.guyader.pro\/?p=3081"},"modified":"2018-04-08T00:01:35","modified_gmt":"2018-04-07T23:01:35","slug":"comment-appliquer-une-fonction-a-une-ou-plusieurs-colonnes-dun-data-frame-et-ajouter-ces-nouvelles-donnees-a-ce-data-frame-ddply","status":"publish","type":"post","link":"https:\/\/thinkr.fr\/abcdr\/comment-appliquer-une-fonction-a-une-ou-plusieurs-colonnes-dun-data-frame-et-ajouter-ces-nouvelles-donnees-a-ce-data-frame-ddply\/","title":{"rendered":"Comment appliquer une fonction \u00e0 une ou plusieurs colonnes d\u2019un data.frame et ajouter ces nouvelles donn\u00e9es \u00e0 ce data.frame ? : ddply()"},"content":{"rendered":"<p>La fonction <strong>ddply()<\/strong>, faisant partie du package plyr, permet d\u2019appliquer une fonction \u00e0 une ou plusieurs colonnes d\u2019un data.frame en fonction des modalit\u00e9s d\u2019une ou deux variables, et d\u2019ajouter ces donn\u00e9es \u00e0 ce data.frame.<\/p>\n<pre><code><br \/>library(plyr)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 # On charge le package plyr\n\n#On construit un data.frame :\n\ndfx &lt;- data.frame(\n\n\u00a0 \u00a0 group &lt;- c(rep('A', 8), rep('B', 15), rep('C', 6)),\n\n\u00a0 \u00a0 sex &lt;- sample(c(\"M\", \"F\"), size = 29, replace = TRUE),\n\n\u00a0 \u00a0 age &lt;- runif(n = 29, min = 18, max = 54))\n\n\u00a0\n\nddply(dfx, .(group, sex), mutate,\n\n\u00a0 \u00a0 mean = round(mean(age), 2),\n\n\u00a0 \u00a0 sd = round(sd(age), 2))\n\n# On obtient la moyenne et l'\u00e9cart type de l\u2019\u00e2ge en fonction du groupe et du sexe\n\n# et on ajoute une colonne \u201cmean\u201d et \u201csd\u201d au data.frame dfx.\n\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>La fonction ddply(), faisant partie du package plyr, permet d\u2019appliquer une fonction \u00e0 une ou plusieurs colonnes d\u2019un data.frame en fonction des modalit\u00e9s d\u2019une ou deux variables, et d\u2019ajouter ces donn\u00e9es \u00e0 ce data.frame. library(plyr)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 # On charge le package plyr #On construit un data.frame : dfx &lt;- data.frame( \u00a0 \u00a0 group &lt;- c(rep(&lsquo;A&rsquo;, 8), rep(&lsquo;B&rsquo;, 15), rep(&lsquo;C&rsquo;, 6)), \u00a0 \u00a0 sex &lt;- sample(c(\u00ab\u00a0M\u00a0\u00bb, \u00ab\u00a0F\u00a0\u00bb), size = 29, replace = TRUE), \u00a0 \u00a0 age &lt;- runif(n = 29, min = 18, max = 54)) \u00a0 ddply(dfx, .(group, sex), mutate, \u00a0 \u00a0 mean = round(mean(age), 2), \u00a0 \u00a0 sd = round(sd(age), 2)) # On obtient la<a class=\"more-link\" href=\"https:\/\/thinkr.fr\/abcdr\/comment-appliquer-une-fonction-a-une-ou-plusieurs-colonnes-dun-data-frame-et-ajouter-ces-nouvelles-donnees-a-ce-data-frame-ddply\/\">Read More &rarr;<\/a><\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"content-type":"","rop_custom_images_group":[],"rop_custom_messages_group":[],"rop_publish_now":"initial","rop_publish_now_accounts":{"twitter_399453572_399453572":""},"rop_publish_now_history":[],"rop_publish_now_status":"pending","jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[8,12,23],"tags":[],"class_list":{"0":"entry","1":"post","2":"publish","3":"author-helene","4":"post-3081","6":"format-standard","7":"category-fonctions-utiles","8":"category-manipulation-de-donnees","9":"category-transformation-de-donnees"},"acf":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p9O7Sx-NH","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts\/3081","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/comments?post=3081"}],"version-history":[{"count":2,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts\/3081\/revisions"}],"predecessor-version":[{"id":4258,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts\/3081\/revisions\/4258"}],"wp:attachment":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/media?parent=3081"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/categories?post=3081"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/tags?post=3081"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}