{"id":3772,"date":"2016-10-06T19:12:45","date_gmt":"2016-10-06T17:12:45","guid":{"rendered":"http:\/\/www.valcon.it\/python\/?p=3772"},"modified":"2025-08-15T12:35:40","modified_gmt":"2025-08-15T10:35:40","slug":"printf","status":"publish","type":"post","link":"https:\/\/www.valcon.it\/python\/printf\/","title":{"rendered":"Stringhe con %"},"content":{"rendered":"\n<p>L&#8217;output della funzione <strong>print<\/strong>() di Python pu\u00f2 essere formattato secondo lo stile della funzione <strong>printf<\/strong>() del linguaggio C<\/p>\n\n\n\n<ul>\n<li>La stringa iniziale <strong>&#8220;&#8230;&#8221;<\/strong> specifica l&#8217;intero output<\/li>\n\n\n\n<li>L&#8217;elenco successivo <strong>%(&#8230;)<\/strong> specifica i dati da inserire nella stringa<\/li>\n\n\n\n<li>I caratteri <strong>% <\/strong>nella stringa sono dei segnaposto per dei dati da visualizzare (con eventuale formattazione)<\/li>\n\n\n\n<li>I dati possono essere variabili\/espressioni\/funzioni<\/li>\n\n\n\n<li>Per formattare i dati si utilizzano i caratteri: <strong>+<\/strong> \/ <strong>&#8211;<\/strong> \/ <strong>.<\/strong> \/ <strong>c<\/strong> \/ <strong>d<\/strong> \/ <strong>e<\/strong> \/ <strong>E<\/strong> \/ <strong>f<\/strong> \/ <strong>F<\/strong> \/\u00a0<strong>i<\/strong> \/ <strong>o<\/strong> \/ <strong>s<\/strong> \/ <strong>x<\/strong> \/ <strong>X<\/strong> \/ <strong>0<\/strong><\/li>\n<\/ul>\n\n\n\n<p>Attenzione&#8230;<\/p>\n\n\n\n<ul>\n<li>La tecnica del <em>print formattato<\/em> \u00e8 considerata <em>obsoleta<\/em> rispetto all&#8217;uso della nuova funzione <a href=\"https:\/\/www.valcon.it\/python\/format\/\" data-type=\"post\" data-id=\"12491\"><strong>format<\/strong>()<\/a>.<br><em>Rimane valida se si utilizza nel linguaggio C&#8230;<\/em><\/li>\n\n\n\n<li>La funzione <strong>format<\/strong>() \u00e8 considerata <em>obsoleta<\/em> rispetto all&#8217;uso delle <strong>F-string<\/strong>.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">1<\/h2>\n\n\n\n<p>Il segnaposto <strong>%s<\/strong> viene sostituito con il valore di una <strong>stringa<\/strong><\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-1 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\ntitolo=&quot;Shrek&quot;\nprint(&quot;Ho visto&quot;, titolo, &quot;al cinema.&quot;)\nprint(&quot;Ho visto %s al cinema.&quot; %(titolo))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\nHo visto Shrek al cinema.\nHo visto Shrek al cinema.\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">2<\/h2>\n\n\n\n<p>Il segnaposto <strong>%c<\/strong> viene sostituito con il valore di un <strong>carattere<\/strong> singolo<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-2 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<p>&#8230;<\/p>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<p>&#8230;<\/p>\n<\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">3<\/h2>\n\n\n\n<p>Il segnaposto <strong>%i<\/strong> (<strong>%d<\/strong>) viene sostituito con il valore di un <strong>intero<\/strong><\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-3 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\nquanti=4\nprint(&quot;Ho svolto %i esercizi.&quot; %(quanti))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\nHo svolto 4 esercizi.\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">4<\/h2>\n\n\n\n<p>Il segnaposto <strong>%f<\/strong> (<strong>%F<\/strong>) viene sostituito con il valore del <strong>float<\/strong> specificato.<br>Di default appare il valore arrotondato alla 6\u00b0 cifra decimale.<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-4 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\nsomma=7.5 \nprint(&quot;Ho speso \u20ac %f al bar.&quot; %(somma))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\nHo speso \u20ac 7.500000 al bar.\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">5<\/h2>\n\n\n\n<p>La cifra dopo il punto specifica il <em>numero di cifre decimali visibili<\/em> del valore float<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-5 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\nsomma=7.5\nprint(&quot;Ho speso \u20ac %.2f al bar.&quot; %(somma))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\nHo speso \u20ac 7.50 al bar.\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">6<\/h2>\n\n\n\n<p>Prova pi\u00f9 segnaposti con specifiche diverse<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-6 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\nx1=0.5\nx2=7.5\nprint(&quot;%.1f*%.1f = %.2f&quot; %(x1, x2, x1*x2))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\n0.5*7.5 = 3.75\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">7<\/h2>\n\n\n\n<p>Il numero dopo <strong>%<\/strong> specifica il numero di&nbsp;colonne (con allineamento a destra)<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\na1=1\na2=12\nx1=0.5\nx2=75.25\nprint(&quot;%2i %5.2f&quot; %(a1, x1))\nprint(&quot;%2i %5.2f&quot; %(a2, x2))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\n_1 _0.50\n12 75.25\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">8<\/h2>\n\n\n\n<p>Lo <strong>0<\/strong>, zero, forza il riempimento con la cifra zero degli spazi prima del numero<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-8 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\n...\nprint(&quot;%04i %5.2f&quot; %(a1, x1))\nprint(&quot;%04i %5.2f&quot; %(a2, x2))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\n0001  0.50\n0012 75.25\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">9<\/h2>\n\n\n\n<p>Il segno <strong>&#8211;<\/strong>, meno, dopo <strong>%<\/strong> specifica l&#8217;allineamento a sinistra<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-9 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\n...\nprint(&quot;%-2i %6.2f&quot; %(a1, x1))\nprint(&quot;%-2i %6.2f&quot; %(a2, x2))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\n1    0.50\n12  75.25\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">10<\/h2>\n\n\n\n<p>Il segno <strong>+<\/strong> forza l&#8217;output del <em>segno<\/em> anche quando il valore \u00e8 positivo<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-10 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\na1=-5\na2=+5\nprint(&quot;&#x5B;%i, %i]&quot; %(a1, a2))\nprint(&quot;&#x5B;%+i, %+i]&quot; %(a1, a2))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\n&#x5B;-5, 5]\n&#x5B;-5, +5]\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">11<\/h2>\n\n\n\n<p>%<strong>%<\/strong> visualizza il carattere <strong>%<\/strong><\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-11 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\nx=7.5\nprint(&quot;Il %.1f%% del capitale investito.&quot; %(x))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\nIl 7.5% del capitale investito.\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">12<\/h2>\n\n\n\n<p>Un numero pu\u00f2 apparire nella notazione scientifica<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-12 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\na=63.5\nprint(&quot;%e&quot; %(a))\nprint(&quot;%E&quot; %(a))\nprint(&quot;%.4e&quot; %(a))\nprint(&quot;%12.4E&quot; %(a))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\n6.350000e+01\n6.350000E+01\n6.3500e+01\n  6.3500E+01\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">13<\/h2>\n\n\n\n<p>Un numero intero pu\u00f2 apparire nelle basi alternative<\/p>\n\n\n\n<ul>\n<li>ottale (<strong>o<\/strong>)<\/li>\n\n\n\n<li>esadecimale minuscolo (<strong>x<\/strong>)<\/li>\n\n\n\n<li>esadecimale maiuscolo (<strong>X<\/strong>)<\/li>\n<\/ul>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-13 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\na=63\nprint(&quot;%o&quot; %(a))\nprint(&quot;%x&quot; %(a))\nprint(&quot;%X&quot; %(a))\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\n77\n3f\n3F\n<\/pre><\/div><\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">14<\/h2>\n\n\n\n<p>All&#8217;interno di <strong>print<\/strong>() si pu\u00f2 utilizzare <strong>end<\/strong>=&#8221;&#8230;&#8221; per rimanere sulla stessa linea<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-layout-14 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; gutter: false; title: ; notranslate\" title=\"\">\nprint(&quot;...&quot; %(...), end=&quot;...&quot;)\n<\/pre><\/div><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<p>&#8230;<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>L&#8217;output della funzione print() di Python pu\u00f2 essere formattato secondo lo stile della funzione printf() del linguaggio C Attenzione&#8230; 1 Il segnaposto %s viene sostituito con il valore di una stringa 2 Il segnaposto %c viene sostituito con il valore di un carattere singolo &#8230; &#8230; 3 Il segnaposto %i (%d) viene sostituito con il &#8230; <a title=\"Stringhe con %\" class=\"read-more\" href=\"https:\/\/www.valcon.it\/python\/printf\/\" aria-label=\"Leggi di pi\u00f9 su Stringhe con %\">Leggi tutto<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[64],"tags":[],"_links":{"self":[{"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/posts\/3772"}],"collection":[{"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/comments?post=3772"}],"version-history":[{"count":102,"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/posts\/3772\/revisions"}],"predecessor-version":[{"id":29408,"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/posts\/3772\/revisions\/29408"}],"wp:attachment":[{"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/media?parent=3772"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/categories?post=3772"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.valcon.it\/python\/wp-json\/wp\/v2\/tags?post=3772"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}