(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)
vprintf — 输出格式化字符串
$format, array $values): int
根据 format （sprintf()
函数文档中有相关描述）参数指定的格式，在一个格式化字符串中显示多个值。
作用与 printf() 函数类似，但是接收一个数组参数，而不是一系列可变数量的参数。
format
format 字符串通常由零或多个指令组成：普通字符（不包含
%）——直接复制到结果，转换规范——获取每个参数的结果。
转换规范遵循此原型：
%[argnum$][flags][width][.precision]specifier.
整数后跟美元符号 $，用于指定转换中要处理的参数数量。
| 标志 | 说明 |
|---|---|
- |
在指定字段宽度时左对齐，默认右对齐 |
+ |
正数的加号 +前缀，默认负数的前缀是负号。
|
(space) |
空格填充结果。这是默认设置。 |
0 |
仅用 0 进行左侧数字填充。使用 s 标志符可以右侧填充。
|
'(char) |
用字符（char）填充结果。 |
要么是整数，表示转换结果应该有多少个字符（最少），要么是 *。如果使用
*，那么宽度将作为额外的整数值提供，位于格式化符号之前。
小数点 .，可选的后跟整数或者 *，其含义取决于格式化符号：
e、E、f、F
标志符：小数点后需要打印的位数（默认是 6）。
g、G、h、H
标志符：这是要打印的最大有效位数。
s 标志符：充当分界点，为字符串设置最大字符限制。
注意: 如果小数点没有明确的精度值，则假设是 0。如果使用
*，则精度将作为额外的整数值提供，位于格式化符号之前。
| 标志符 | 说明 |
|---|---|
% |
字面意思的百分号字符。不需要参数。 |
b |
参数视为整数并以二进制数字呈现。 |
c |
参数视为整数并以 ASCII 字符呈现。 |
d |
参数视为整数并以（有符号）十进制数字呈现。 |
e |
参数当做科学符号处理（例如 1.2e+2）。 |
E |
与 e 标志符相同，但使用大写字母（例如 1.2E+2）。
|
f |
参数当做浮点数处理且作为浮点数呈现（locale aware）。 |
F |
参数当做浮点数处理且作为浮点数呈现（non-locale aware）。 |
g |
通用格式。 Let P equal the precision if nonzero, 6 if the precision is omitted, or 1 if the precision is zero. Then, if a conversion with style E would have an exponent of X: If P > X ≥ −4, the conversion is with style f and precision P − (X + 1). Otherwise, the conversion is with style e and precision P − 1. |
G |
Like the g specifier but uses
E and f.
|
h |
Like the g specifier but uses F.
Available as of PHP 8.0.0.
|
H |
Like the g specifier but uses
E and F. Available as of PHP 8.0.0.
|
o |
参数视为整数并以八进制数字来呈现。 |
s |
参数视为字符串来呈现。 |
u |
参数视为整数并以无符号十进制数字呈现。 |
x |
参数视为整数并作为十六进制数字呈现（带小写字母）。 |
X |
参数视为整数并作为十六进制数字呈现（带大写字母）。 |
c 类型标志符忽略填充和宽度
Attempting to use a combination of the string and width specifiers with character sets that require more than one byte per character may result in unexpected results
变量将会强制转换为适合标志符的类型：
| 类型 | 标志符 |
|---|---|
| string | s |
| int |
d,
u,
c,
o,
x,
X,
b
|
| float |
e,
E,
f,
F,
g,
G,
h,
H
|
values
返回输出字符串的长度。
从 PHP 8.0.0 开始，如果参数个数为零，将抛出 ValueError。在 PHP 8.0.0 之前，会发出 E_WARNING。
从 PHP 8.0.0 开始，如果 [width] 小于零或大于 PHP_INT_MAX，则会抛出
ValueError。在 PHP 8.0.0 之前，会发出 E_WARNING。
从 PHP 8.0.0 开始，如果 [precision] 小于零或大于 PHP_INT_MAX，则会抛出
ValueError。在 PHP 8.0.0 之前，会发出 E_WARNING。
从 PHP 8.0.0 开始，当传递的参数少于所需的参数时会抛出 ValueError。在 PHP 8.0.0 之前，返回 false 并发出 E_WARNING。
| 版本 | 说明 |
|---|---|
| 8.0.0 |
此函数失败时不再返回 false。
|
| 8.0.0 |
如果参数个数为零则抛出 ValueError；以前该函数则会发出 E_WARNING。
|
| 8.0.0 |
如果 [width] 小于零或大于 PHP_INT_MAX，则抛出 ValueError；以前该函数则会发出 E_WARNING。
|
| 8.0.0 |
如果 [precision] 小于零或大于 PHP_INT_MAX，则抛出 ValueError；以前该函数则会发出 E_WARNING。
|
| 8.0.0 |
当传递的参数少于所需的参数时抛出 ValueError；以前该函数则会发出 E_WARNING。
|
示例 #1 vprintf()：补零整数
<?php
vprintf("%04d-%02d-%02d", explode('-', '1988-8-1'));
?>以上示例会输出：
1988-08-01
If, instead of an array, you pass an object PHP will automatically cast the object as an array so you can use it directly in vprintf.
<?php
$object = new stdClass();
$object->Property1 = 'Value 1';
$object->Property2 = 'Value 2';
vprintf('%-20s %-20s', $object);
/* will output
Value 1 Value 2
*/
?>Using the ... operator, vprintf($format, $array) is basically just printf($format, ...$array).To toolofthesystem at gmail dot com:
You don't need to use output buffering with vprintf() because you can use vsprintf(), which has the same functionality as vprintf(), except that it returns the resulting string instead of outputting it.<?php
$string = 'The site runs on PHP '.phpversion();
preg_match('/php ((\d)\.\d\.\d+)/i',$string,$matches);
print_r($matches);
vprintf('Match: %s<br /> Version %s; Major:%d.',$matches);
?>
output:
Array ( [0] => PHP 5.2.5 [1] => 5.2.5 [2] => 5 )
Match: PHP 5.2.5 Version 5.2.5; Major:5.
For preg_match:
If matches is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1] will have the text that matched the first captured parenthesized subpattern, and so on.Another way to display arrays is use an array_walk(). This can be useful inline echo/print where a foreach wouldn't work, e.g.
<?php
echo "These errors: ", (unset)array_walk($msgs, function($a) { echo "<p>$a</p>"; } ), "must be corrected.";
?>This function comes useful sometimes when trying to list information returned from MySQL:
function print_sql($query,$printf){
$sql_sql = mysql_query($query);
while($sql = mysql_fetch_row($sql_sql)){
vprintf($printf,$sql);
}
}
Unfortunately, this seems to sneak its way past output buffering when I tried creating an argument to allow it to be contained in a returned string... either that or I didn't do it right.For blocks of text, sprintf() is slow according to my tests.
Also, having the mapping between place-holders and the list of actual variables or datastructures often makes this code difficult to read. But the printf() family are widely supported and have a huge range of nice features. Performance is a cold mistress though!
From an ease-of-reading and maintenance, debugging point of view, I much prefer HEREDOC and "...{$variable}..." methods.
For a block of HTML markup with place holders, the fastest by far was:-
?>
<div> markup etc<?= $variable ?>more markup
<?
My tests comprised 20 runs of a loop of 1 million iterations with output buffering, ditching the buffer on each loop.
The timings ranged from average 2.1msec/million repetitions for the <?= $var ?> method up to 7.6msec/million using printf().
I'll try some benchmarking tools too, since I just wrote this myself and it could be introducing bias, but they've run on dev servers with low load.
Hopefully interesting.i know that you can use %1$s or %3$s to select the first or third string but how can you or can you use array names to select it
something like %'user'$s $'email'$s
i tend to add things to my databases over time and this could save loads of recoding