％S在PHP，HTML或XML中的含义是什么？ [英] What does %S mean in PHP, HTML or XML?

问题描述

我正在查看 Webmonkey的PHP和MySql教程，第2课。我认为这是一个PHP文字。 ％s 是什么意思？它至少在第一对代码块中的while循环中位于 print_f（）函数中。

printf（< tr>< td>％s％s< / td>< td>％s< / td>< / tr> n，...



示例：

  $ str1 ='best'; 
 $ str2 ='world'; 
 
 $ say = sprintf（'Tivie是％s！中的％s！'，$ str1 ，$ str2）; 
 echo $ say; 
  

这会输出：

Tivie是世界上最好的！

：有更多的占位符（％s表示字符串，％d表示十进制数字，等等......）





订单：

传递参数的顺序数。如果你用$ str2转换$ str1作为

  $ say = sprintf（'Tivie是％s中的％s！' ，$ str2，$ str1）; 
  

它会打印

$ b $

然而，你可以改变参数的阅读顺序，像这样：

  $ say = sprintf（'Tivie是％1 $ s！中的％2 $ s'，$ str2， $ STR1）; 
  

这将正确地打印句子。

---

另外，请记住，PHP是一种动态语言，不需要（或支持）明确的类型定义。这意味着它根据需要处理变量类型。在sprint中，它意味着如果你传递一个字符串作为数字占位符（％d）的参数，那么该字符串将被转换为数字（int，float ...），这可能会产生奇怪的结果。以下是一个例子：

  $ onevar = 2; 
 $ anothervar ='pocket'; 
 $ say = sprintf（'我有％d巧克力在我的％d。'，$ onevar，$ anothervar）; 
 echo $ say; 
  

这会打印

我的巧克力有2个。

更多阅读 PHPdocs

I'm looking at Webmonkey's PHP and MySql Tutorial, Lesson 2. I think it's a php literal. What does %s mean? It's inside the print_f() function in the while loops in at least the first couple of code blocks.

printf("<tr><td>%s %s</td><td>%s</td></tr>n", ...

解决方案

with printf or sprintf characters preceded by the % sign are placeholders (or tokens). They will be replaced by a variable passed as an argument.

Example:

$str1 = 'best';
$str2 = 'world';

$say = sprintf('Tivie is the %s in the %s!', $str1, $str2);
echo $say;

This will output:

Tivie is the best in the world!

Note: There are more placeholders (%s for string, %d for dec number, etc...)

---

Order:

The order in which you pass the arguments counts. If you switch $str1 with $str2 as

$say = sprintf('Tivie is the %s in the %s!', $str2, $str1); 

it will print

"Tivie is the world in the best!"

You can, however, change the reading order of arguments like this:

$say = sprintf('Tivie is the %2$s in the %1$s!', $str2, $str1);

which will print the sentence correctly.

---

Also, keep in mind that PHP is a dynamic language and does not require (or support) explicit type definition. That means it juggles variable types as needed. In sprint it means that if you pass a "string" as argument for a number placeholder (%d), that string will be converted to a number (int, float...) which can have strange results. Here's an example:

$onevar = 2;
$anothervar = 'pocket';
$say = sprintf('I have %d chocolate(s) in my %d.', $onevar, $anothervar);
echo $say;

this will print

I have 2 chocolate(s) in my 0.

More reading at PHPdocs

这篇关于％S在PHP，HTML或XML中的含义是什么？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！