{"id":3091,"date":"2015-07-09T08:30:49","date_gmt":"2015-07-09T07:30:49","guid":{"rendered":"https:\/\/abcdr.guyader.pro\/?p=3091"},"modified":"2018-04-08T00:01:48","modified_gmt":"2018-04-07T23:01:48","slug":"comment-obtenir-une-table-de-contingence-melt-acast-dcast","status":"publish","type":"post","link":"https:\/\/thinkr.fr\/abcdr\/comment-obtenir-une-table-de-contingence-melt-acast-dcast\/","title":{"rendered":"Comment obtenir une table de contingence ? : melt, acast, dcast."},"content":{"rendered":"<p>Les fonctions <b>acast() <\/b>et <b>dcast() <\/b>associ\u00e9es \u00e0 la fonction <b>melt()<\/b>, du package <b>reshape2<\/b>, permettent d\u2019obtenir une table de contingence.<\/p>\n<pre><code><br \/>library(reshape2) # On charge le package reshape2\n\nairquality\n\naqm &lt;- melt(airquality, id=c(\"Month\", \"Day\"), na.rm=TRUE)\n\n#On passe d\u2019un format \u201cWide\u201d \u00e0 un format \u201cLong\u201d\n\n\n\n#Pour un array\n\n\n\nacast(aqm, Month ~ variable, mean)\n\n#On obtient une table de contingence contenant la moyenne de chaque variable en fonction du mois\n\n\n\nacast(aqm, Month ~ variable, mean, margins = TRUE)\n\n#On ajoute les moyennes de chaque variable pour l'ensemble des mois\n\n#et les moyennes de chaque mois pour l'ensemble des variables\n\n\n\n#Pour un data.frame\n\n\n\ndcast(aqm, Month ~ variable, mean, margins = c(\"Month\", \"variable\"))\n\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Les fonctions acast() et dcast() associ\u00e9es \u00e0 la fonction melt(), du package reshape2, permettent d\u2019obtenir une table de contingence. library(reshape2) # On charge le package reshape2 airquality aqm &lt;- melt(airquality, id=c(\u00ab\u00a0Month\u00a0\u00bb, \u00ab\u00a0Day\u00a0\u00bb), na.rm=TRUE) #On passe d\u2019un format \u201cWide\u201d \u00e0 un format \u201cLong\u201d #Pour un array acast(aqm, Month ~ variable, mean) #On obtient une table de contingence contenant la moyenne de chaque variable en fonction du mois acast(aqm, Month ~ variable, mean, margins = TRUE) #On ajoute les moyennes de chaque variable pour l&rsquo;ensemble des mois #et les moyennes de chaque mois pour l&rsquo;ensemble des variables #Pour un data.frame dcast(aqm, Month ~ variable, mean, margins =<a class=\"more-link\" href=\"https:\/\/thinkr.fr\/abcdr\/comment-obtenir-une-table-de-contingence-melt-acast-dcast\/\">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-3091","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-NR","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts\/3091","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=3091"}],"version-history":[{"count":2,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts\/3091\/revisions"}],"predecessor-version":[{"id":4266,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/posts\/3091\/revisions\/4266"}],"wp:attachment":[{"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/media?parent=3091"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/categories?post=3091"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thinkr.fr\/abcdr\/wp-json\/wp\/v2\/tags?post=3091"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}