sprintf

(PHP 4, PHP 5, PHP 7, PHP 8)

sprintf返回格式化字符串

说明

sprintf(string $format, mixed ...$values): string

返回一个根据格式化字符串 format 生成的字符串。

参数

format

The format string is composed of zero or more directives: ordinary characters (excluding %) that are copied directly to the result and conversion specifications, each of which results in fetching its own parameter.

A conversion specification follows this prototype: %[argnum$][flags][width][.precision]specifier.

Argnum

An integer followed by a dollar sign $, to specify which number argument to treat in the conversion.

Flags
Flag 说明
- Left-justify within the given field width; Right justification is the default
+ Prefix positive numbers with a plus sign +; Default only negative are prefixed with a negative sign.
(space) Pads the result with spaces. This is the default.
0 Only left-pads numbers with zeros. With s specifiers this can also right-pad with zeros.
'(char) Pads the result with the character (char).

Width

An integer that says how many characters (minimum) this conversion should result in.

Precision

A period . followed by an integer who's meaning depends on the specifier:

  • For e, E, f and F specifiers: this is the number of digits to be printed after the decimal point (by default, this is 6).
  • For g, G, h and H specifiers: this is the maximum number of significant digits to be printed.
  • For s specifier: it acts as a cutoff point, setting a maximum character limit to the string.

注意: If the period is specified without an explicit value for precision, 0 is assumed.

注意: Attempting to use a position specifier greater than PHP_INT_MAX will generate warnings.

Specifiers
Specifier 说明
% A literal percent character. No argument is required.
b The argument is treated as an integer and presented as a binary number.
c The argument is treated as an integer and presented as the character with that ASCII.
d The argument is treated as an integer and presented as a (signed) decimal number.
e The argument is treated as scientific notation (e.g. 1.2e+2).
E Like the e specifier but uses uppercase letter (e.g. 1.2E+2).
f The argument is treated as a float and presented as a floating-point number (locale aware).
F The argument is treated as a float and presented as a floating-point number (non-locale aware).
g

General format.

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 The argument is treated as an integer and presented as an octal number.
s The argument is treated and presented as a string.
u The argument is treated as an integer and presented as an unsigned decimal number.
x The argument is treated as an integer and presented as a hexadecimal number (with lowercase letters).
X The argument is treated as an integer and presented as a hexadecimal number (with uppercase letters).

警告

The c type specifier ignores padding and width

警告

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

Variables will be co-erced to a suitable type for the specifier:

Type Handling
Type Specifiers
string s
int d, u, c, o, x, X, b
float e, E, f, F, g, G, h, H

values

返回值

返回一个根据格式化字符串 format 生成的字符串。

更新日志

版本 说明
8.0.0 此函数失败时不再返回 false

范例

示例 #1 参数替换

支持按顺序用参数替换格式字符串里的占位符。

<?php
$num 
5;
$location 'tree';

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

以上例程会输出:

There are 5 monkeys in the tree

假设,我们想把它国际化,在一个单独的文件中创建格式字符串,我们将它重写为:

<?php
$format 
'The %s contains %d monkeys';
echo 
sprintf($format$num$location);
?>

我们现在有一个问题。 格式字符串中占位符的顺序与代码中参数的顺序不匹配。 我们希望保持代码原样,并在格式字符串中简单地指出占位符引用的参数。 我们可以这样写格式化字符串:

<?php
$format 
'The %2$s contains %1$d monkeys';
echo 
sprintf($format$num$location);
?>

另外一个好处是占位符可以重复使用,而无需在代码中添加更多参数。

<?php
$format 
'The %2$s contains %1$d monkeys.
           That\'s a nice %2$s full of %1$d monkeys.'
;
echo 
sprintf($format$num$location);
?>

当使用参数替换时,n$ 位置指示符 必须紧跟在百分号(%)之后,在任何其他指示符之前,如下所示。

示例 #2 指定填充字符

<?php
echo sprintf("%'.9d\n"123);
echo 
sprintf("%'.09d\n"123);
?>

以上例程会输出:

......123
000000123

示例 #3 位置说明符与其他说明符

<?php
$format 
'The %2$s contains %1$04d monkeys';
echo 
sprintf($format$num$location);
?>

以上例程会输出:

The tree contains 0005 monkeys

示例 #4 sprintf(): 零填充整数

<?php
$isodate 
sprintf("%04d-%02d-%02d"$year$month$day);
?>

示例 #5 sprintf(): 货币格式

<?php
$money1 
68.75;
$money2 54.35;
$money $money1 $money2;
echo 
$money;
echo 
"\n";
$formatted sprintf("%01.2f"$money);
echo 
$formatted;
?>

以上例程会输出:

123.1
123.10

示例 #6 sprintf(): 科学记数法

<?php
$number 
362525200;

echo 
sprintf("%.3e"$number);
?>

以上例程会输出:

3.625e+8

参见