June 2005
Intermediate to advanced
794 pages
18h 27m
German
Content preview from PHP 5 KochbuchBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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2.1 Prüfen, ob ein String eine gültige Zahl enthält
Problem
Sie möchten sicherstellen, dass ein String eine Zahl enthält. Beispielsweise möchten Sie eine Altersangabe validieren, die ein Benutzer in das Eingabefeld eines Formulars geschrieben hat.
Lösung
Verwenden Sie is_numeric( ):
if (is_numeric('fünf')) { /* falsch */ }
if (is_numeric(5)) { /* wahr */ }
if (is_numeric('5')) { /* wahr */ }
if (is_numeric(-5)) { /* wahr */ }
if (is_numeric('-5')) { /* wahr */ }Diskussion
Die Funktion is_numeric( ) kann nicht nur mit Zahlen arbeiten, sondern auch auf numerische Strings angewendet werden. Der Unterschied besteht hier darin, dass die ganze Zahl 5 und der String 5 in PHP technisch gesehen nicht dasselbe sind.[2]
Es ist hilfreich, dass is_numeric( ) auch ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.