%S 在 PHP、HTML 或 XML 中是什么意思？

What does %S mean in PHP, HTML or XML?

提问by Wolfpack'08

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

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。什么%s意思？它print_f()位于至少前几个代码块中的 while 循环中的函数内部。

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

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

回答by Tivie

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

以 % 符号开头的 printf 或 sprintf 字符是占位符（或标记）。它们将被作为参数传递的变量替换。

Example:

例子：

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

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

This will output:

这将输出：

Tivie is the best in the world!

蒂维是世界上最好的！

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

注意：有更多的占位符（%s 代表字符串，%d 代表十进制数字，等等...）

---

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Order:

命令：

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

您传递参数的顺序很重要。如果您将 $str1 与 $str2 切换为

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

it will print

它会打印

"Tivie is the world in the best!"

“蒂维是世界上最好的！”

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

但是，您可以像这样更改参数的阅读顺序：

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

which will print the sentence correctly.

这将正确打印句子。

---

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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:

另外，请记住 PHP 是一种动态语言，不需要（或支持）显式类型定义。这意味着它会根据需要处理变量类型。在 sprint 中，这意味着如果您传递一个“字符串”作为数字占位符 (%d) 的参数，该字符串将被转换为一个数字 (int, float...)，这可能会产生奇怪的结果。下面是一个例子：

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

this will print

这将打印

I have 2 chocolate(s) in my 0.

我的 0 中有 2 个巧克力。

More reading at PHPdocs

更多阅读PHPdocs

回答by Ned Batchelder

In printf, %sis a placeholder for data that will be inserted into the string. The extra arguments to printfare the values to be inserted. They get associated with the placeholders positionally: the first placeholder gets the first value, the second the second value, and so on.

In printf,%s是将插入到字符串中的数据的占位符。的额外参数printf是要插入的值。它们在位置上与占位符相关联：第一个占位符获取第一个值，第二个占位符获取第二个值，依此类推。

回答by rdo

%sis a type specifier which will be replaced to valuable's value (string) in case of %s.

%s是一个类型说明符，在%s.

Besides %syou can use other specifiers, most popular are below:

除了%s您可以使用其他说明符之外，最流行的是以下：

d - the argument is treated as an integer, and presented as a (signed) decimal number.

d - 参数被视为整数，并表示为（有符号）十进制数。

f - the argument is treated as a float, and presented as a floating-point number (locale aware).

f - 参数被视为浮点数，并显示为浮点数（本地环境感知）。

s - the argument is treated as and presented as a string.

s - 参数被视为并显示为字符串。

回答by David

$num = 5; 
$location = 'tree';

$format = 'There are %d monkeys in the %s'; 
echo sprintf($format, $num, $location); 

Will output: "There are 5 monkeys in the tree."

将输出：“树上有 5 只猴子。”

回答by Emeka Augustine

The printf()or sprintf()function writes a formatted string to a variable. Here is the Syntax:

该printf()或sprintf()功能的格式化字符串到变量。这是语法：

sprintf(format,arg1,arg2,arg++)

format:

格式：

• %% - Returns a percent sign
• %b - Binary number
• %c - The character according to the ASCII value
• %d - Signed decimal number (negative, zero or positive)
• %e - Scientific notation using a lowercase (e.g. 1.2e+2)
• %E - Scientific notation using a uppercase (e.g. 1.2E+2)
• %u - Unsigned decimal number (equal to or greater than zero)
• %f - Floating-point number (local settings aware)
• %F - Floating-point number (not local settings aware)
• %g - shorter of %e and %f
• %G - shorter of %E and %f
• %o - Octal number
• %s - String
• %x - Hexadecimal number (lowercase letters)
• %X - Hexadecimal number (uppercase letters)

• %% - 返回百分号
• %b - 二进制数
• %c - 根据 ASCII 值的字符
• %d - 有符号十进制数（负、零或正）
• %e - 使用小写的科学记数法（例如 1.2e+2）
• %E - 使用大写的科学记数法（例如 1.2E+2）
• %u - 无符号十进制数（等于或大于零）
• %f - 浮点数（本地设置感知）
• %F - 浮点数（不知道本地设置）
• %g - %e 和 %f 中的较短
• %G - %E 和 %f 中的较短
• %o - 八进制数
• %s - 字符串
• %x - 十六进制数（小写字母）
• %X - 十六进制数（大写字母）

arg1:

参数1：

• The argument to be inserted at the first %-signin the format string..(Required.)

• 要在格式字符串中的第一个% 符号处插入的参数..（必需。）

arg2:

参数2：

• The argument to be inserted at the second %-signin the format string. (Optional)

• 要在格式字符串中的第二个% 符号处插入的参数。（可选的）

arg++:

参数++：

• The argument to be inserted at the third, fourth, etc. %-signin the format string (Optional)

• 在第三被插入的参数，第四等％-sign格式字符串（可选）

Example 1:

示例 1：

$number = 9;
$str = "New York";
$txt = sprintf("There are approximately %u million people in %s.",$number,$str);
echo $txt;

This will output:

这将输出：

There are approximately 9million people in New York.

大约有9百万人在New York。

The arg1, arg2, arg++parameters will be inserted at percent (%) signs in the main string. This function works "step-by-step". At the first % sign, arg1 is inserted, at the second % sign, arg2 is inserted, etc.

的ARG1，ARG2，ARG ++参数将在主串以百分比（％）的标志插入。此功能“逐步”工作。在第一个 % 符号处插入 arg1，在第二个 % 符号处插入 arg2，以此类推。

Note: If there are more % signs than arguments, you must use placeholders. A placeholder is inserted after the % sign, and consists of the argument- number and "\$". Let see another Example:

注意：如果 % 符号多于参数，则必须使用占位符。占位符插入在 % 符号之后，由参数编号和“\$”组成。让我们看另一个例子：

Example 2

示例 2

$number = 123;
$txt = sprintf("With 2 decimals: %1$.2f
<br>With no decimals: %1$u",$number);
echo $txt;

This will output:

这将输出：

With 2 decimals: 123.00
With no decimals: 123

有 2 位小数：123.00
没有小数：123

Another important tip to remember is that:

要记住的另一个重要提示是：

With printf()and sprintf()functions, escape character is not backslash '\' but rather '%'. Ie. to print '%' character you need to escape it with itself:

对于printf()和sprintf()函数，转义字符不是反斜杠“\”而是“%”。IE。要打印 '%' 字符，您需要用它自己转义它：

printf('%%%s%%', 'Nigeria Naira');

printf('%%%s%%', 'Nigeria Naira');

This will output:

这将输出：

%Nigeria Naira%

%尼日利亚奈拉%

Feel free to explore the official PHP Documentation

随意浏览官方PHP 文档