{"id":2570,"date":"2019-07-03T17:59:37","date_gmt":"2019-07-03T16:59:37","guid":{"rendered":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/?page_id=2570"},"modified":"2019-07-03T18:06:42","modified_gmt":"2019-07-03T17:06:42","slug":"f-linstruction-conditionnelle-if","status":"publish","type":"page","link":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/python\/ii-les-principales-structures-algorithmiques-en-python\/f-linstruction-conditionnelle-if\/","title":{"rendered":"F L&rsquo;instruction conditionnelle if"},"content":{"rendered":"\n<p>Cette\ninstruction permet de d\u00e9terminer si d&rsquo;autres instructions doivent \u00eatre\nex\u00e9cut\u00e9es ou non.\n\nCette instruction se\nd\u00e9cline en 3 variantes possibles&nbsp;:\n\n\n\n<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Si &#8230; alors &#8230;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Si &#8230; alors &#8230; Sinon &#8230;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li> &#8211; Si &#8230; alors &#8230; Sinon si &#8230; alors &#8230; Sinon &#8230; <\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-content\/uploads\/sites\/4\/2019\/07\/Attention.svg\" alt=\"\" class=\"wp-image-2538\" width=\"81\" height=\"75\" \/><\/figure>\n\n\n\n<p>Les retours \u00e0 la ligne et les d\u00e9calages (indentation) remplacent le \u00ab\u00a0alors\u00a0\u00bb.<\/p>\n\n\n\n<p>Exemple 1 :<\/p>\n\n\n\n<table class=\"wp-block-table is-style-stripes\"><tbody><tr><td>Editeur<\/td><\/tr><tr><td>n = int(input(\u00ab\u00a0Entrer un nombre entier entre 0 et 10 :\u00a0\u00bb)) <br>if n&gt;=3 :     <br>    m = 2*n<br>print(m)<\/td><\/tr><tr><td>Console (apr\u00e8s avoir rempli la donn\u00e9e demand\u00e9e par 4)<\/td><\/tr><tr><td>&gt;&gt;&gt;<br>8<br>&gt;&gt;&gt;<\/td><\/tr><\/tbody><\/table>\n\n\n\n<p>Exemple 2 : <\/p>\n\n\n\n<p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nDans la ligne <em>if<\/em> ce sont des <em>==<\/em> et non\ndes <em>= <\/em>car il s&rsquo;agit d&rsquo;un test (==) et\nnon d&rsquo;une affectation de valeur \u00e0 une variable (=).\n\n\n\n<\/p>\n\n\n\n<table class=\"wp-block-table is-style-stripes\"><tbody><tr><td>Editeur<\/td><\/tr><tr><td>p1 = eval(input(\u00ab\u00a0Entrer la proportion d&rsquo;individus de ph\u00e9notype [vg+;eb+] issus d\u2019un croisement-test :\u00a0\u00bb)) <br>p2 = eval(input(\u00ab\u00a0Entrer la proportion d&rsquo;individus de ph\u00e9notype [vg;eb] issus d\u2019un croisement-test :\u00a0\u00bb)) <br>p3 = eval(input(\u00ab\u00a0Entrer la proportion d&rsquo;individus de ph\u00e9notype [vg+;eb] issus d\u2019un croisement-test :\u00a0\u00bb)) <br>p4 = eval(input(\u00ab\u00a0Entrer la proportion d&rsquo;individus de ph\u00e9notype [vg;eb+] issus d\u2019un croisement-test :\u00a0\u00bb))<br>if p1==1\/4 and p2==1\/4 and p3==1\/4 and p4==1\/4 :     <br>    brassage = &lsquo;interchromosomique&rsquo; <br>else :     <br>   brassage = &lsquo;intrachromosomique&rsquo;  <br>print(brassage)<\/td><\/tr><tr><td>Console (apr\u00e8s avoir rempli les donn\u00e9es demand\u00e9es par 1\/4)<\/td><\/tr><tr><td>&gt;&gt;&gt;<br>interchromosomique<br>&gt;&gt;&gt;<\/td><\/tr><\/tbody><\/table>\n\n\n\n<p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nExemple 3&nbsp;:\n\n\n\n<\/p>\n\n\n\n<table class=\"wp-block-table is-style-stripes\"><tbody><tr><td>Editeur<\/td><\/tr><tr><td>coeff_directeur_roche_1 = 0.4<br>coeff_directeur_roche_2 = eval(input(\u00ab\u00a0Entrer le coefficient directeur de la droite isochrone de la roche 2 :\u00a0\u00bb))<br><br>if coeff_directeur_roche_1 &gt; coeff_directeur_roche_2 :<br>     roche_1 = &lsquo; est plus vieille&rsquo;<br>elif coeff_directeur_roche_1==coeff_directeur_roche_2 :<br>     roche_1 = &lsquo;a le m\u00eame \u00e2ge&rsquo;<br>else :<br>     roche_1 = &lsquo;est moins vieille&rsquo;<br>print(&lsquo;La roche 1&prime;, roche_1,&rsquo;que la roche 2.&rsquo;)<\/td><\/tr><tr><td>Console (apr\u00e8s avoir rempli la donn\u00e9e demand\u00e9e (ici 0.4))<\/td><\/tr><tr><td>&gt;&gt;&gt;<br>La roche 1 a le m\u00eame \u00e2ge que la roche 2.<br>&gt;&gt;&gt;<\/td><\/tr><\/tbody><\/table>\n","protected":false},"excerpt":{"rendered":"<p>Cette instruction permet de d\u00e9terminer si d&rsquo;autres instructions doivent \u00eatre ex\u00e9cut\u00e9es ou non. Cette instruction se d\u00e9cline en 3 variantes possibles&nbsp;: Si &#8230; alors &#8230; Si &#8230; alors &#8230; Sinon &#8230; &#8211; Si &#8230; alors &#8230; Sinon si &#8230; alors &#8230; Sinon &#8230; Les retours \u00e0 la ligne et les d\u00e9calages (indentation) remplacent le \u00ab\u00a0alors\u00a0\u00bb. &hellip; <\/p>\n<p><a class=\"more-link btn\" href=\"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/python\/ii-les-principales-structures-algorithmiques-en-python\/f-linstruction-conditionnelle-if\/\">Lire la suite<\/a><\/p>\n","protected":false},"author":8,"featured_media":0,"parent":2526,"menu_order":6,"comment_status":"closed","ping_status":"closed","template":"template-onecolumn.php","meta":{"footnotes":""},"class_list":["post-2570","page","type-page","status-publish","hentry","nodate","item-wrap"],"_links":{"self":[{"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-json\/wp\/v2\/pages\/2570","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-json\/wp\/v2\/comments?post=2570"}],"version-history":[{"count":3,"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-json\/wp\/v2\/pages\/2570\/revisions"}],"predecessor-version":[{"id":2575,"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-json\/wp\/v2\/pages\/2570\/revisions\/2575"}],"up":[{"embeddable":true,"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-json\/wp\/v2\/pages\/2526"}],"wp:attachment":[{"href":"https:\/\/ent2d.ac-bordeaux.fr\/disciplines\/svt\/wp-json\/wp\/v2\/media?parent=2570"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}