mb_strimwidth

(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)

mb_strimwidth — 获取按指定宽度截断的字符串

说明

mb_strimwidth(
    string $string,
    int $start,
    int $width,
    string $trim_marker = "",
    ?string $encoding = null
): string

将 string string 截断到指定 width。其中半角字符计为 1，全角字符计为 2。有关东亚字符宽度的详细信息，请参阅 » http://www.unicode.org/reports/tr11/。

参数

string

要截断的 string。

start

开始位置的偏移。从这些字符数开始的截取字符串。（默认是 0 个字符） 如果 start 是负数，就是字符串结尾处的字符数。

width

所需修剪的宽度。如果指定负宽度，则从字符串末尾开始计数。

注意:

从 PHP 8.3.0 起，传递负宽度已被弃用。

trim_marker

当字符串被截断的时候，将此字符串添加到截断后的末尾。

encoding

encoding 参数为字符编码。如果省略或是 null，则使用内部字符编码。

返回值

截断后的 string。如果设置了 trim_marker，还将结尾处的字符替换为 trim_marker ，并符合 width 的宽度。

更新日志

版本 说明
8.3.0 将负的 width 传递给 mb_strimwidth() 现已废弃。
8.0.0 现在 encoding 可以为 null。
7.1.0 支持负数的 start 和 width。

示例

示例 #1 mb_strimwidth() 示例

<?php
echo mb_strimwidth("Hello World", 0, 10, "...");
// 输出 Hello W...
?>

参见

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用户贡献的备注 2 notes

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2
dregad at NOSPAM-mantisbt dot org
1 year ago
I see a lot of usage in the field where people rely on this function to truncate a string to a given length and append some chars at the end following example #1 in the above documentation.

While this works just fine with Western alphabets, it should be noted that a string's width is NOT necessarily the same as its length.

In Chinese, Japanese and Korean, some characters can be represented as full or half width, which may lead to unexpected results...

<?php
$str = ['English' => 'Switzerland',
'Half width' => 'ｽｲｽ',
'Full width' => 'スイス',
];
foreach ($str as $w => $s) {
printf("%-10s: %s (bytes=%d chars=%d width=%d)\nSubstring : %s\nTrim width: %s\n\n",
$w, $s,
strlen($s), mb_strlen($s), mb_strwidth($s),
mb_substr($s, 0, 3),
mb_strimwidth($s, 0, 3)
);
}
/* Output
# With ASCII, chars == width, so everything works as expected
English : Switzerland (bytes=11 chars=11 width=11)
Substring : Swi
Trim width: Swi

# With half-width katakanas, it works too
Half width: ｽｲｽ (bytes=9 chars=3 width=3)
Substring : ｽｲｽ
Trim width: ｽｲｽ

# Full-width katakanas are twice as wide, so we only get the 1st 'su' !
Full width: スイス (bytes=9 chars=3 width=6)
Substring : スイス
Trim width: ス
*/
>?
up
1
jamesgrimshaw2006 at gmail dot com
1 year ago
mb_strimwidth will only append "trim_marker" if the string is over the width.

*test code*
$HashTags = 'Results';
$socialmediatext = 'abcdefghijklmnopqrstuvwxyz';
for( $i=0; $i<=20; $i++ )
{
$socialmediatext .= '.';
$Twittext = mb_strimwidth($socialmediatext,0,35,$HashTags);
echo "<p>[".strlen($Twittext)."]$Twittext</p>";
}

*output*
[27]abcdefghijklmnopqrstuvwxyz.
[28]abcdefghijklmnopqrstuvwxyz..
[29]abcdefghijklmnopqrstuvwxyz...
[30]abcdefghijklmnopqrstuvwxyz....
[31]abcdefghijklmnopqrstuvwxyz.....
[32]abcdefghijklmnopqrstuvwxyz......
[33]abcdefghijklmnopqrstuvwxyz.......
[34]abcdefghijklmnopqrstuvwxyz........
[35]abcdefghijklmnopqrstuvwxyz.........
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
[35]abcdefghijklmnopqrstuvwxyz..Results
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