PHP can easily intercept mixed Chinese and English strings with just 2 lines of code!

When it comes to Chinese and English mixed counting and interception, the first thing that comes to mind is ascii, hexadecimal, regular matching, and loop counting.

Today I will share with you the mb extension of php to teach you how to process strings easily.

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First introduce to you the functions used:

mb_strwidth($str, $encoding) returns the width of the string

$str The string to be calculated

$encoding The encoding to be used, such as utf8, gbk

mb_strimwidth($str, $start, $width, $tail, $encoding) intercepts the string by width

$str The string to be intercepted

$start The position from which to start interception, the default is 0

$width The width to be intercepted

$tail is appended to the string after the intercepted string, commonly used is...

$encoding The encoding to use

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I will give you an example below:

/**
 * utf8 encoding format
 * 1 Chinese character occupies 3 bytes
 * What we hope is that 1 Chinese character occupies 2 bytes,
 * Because from the width point of view, the position occupied by 2 English letters is equivalent to 1 Chinese character
*/

// Test string
$str = 'aaaaahahaaaaahahahaaa';
echo strlen($str); // only Use strlen to output 25 bytes

// You must specify the encoding, otherwise PHP's internal code mb_internal_encoding() will be used to view the internal code
// Use mb_strwidth to output a string with a width of 20 and use utf8 encoding
echo mb_strwidth($ str, 'utf8');

// Only intercept if the width is greater than 10
if(mb_strwidth($str, 'utf8')>10){
 // Set here to intercept from 0, take 10 appends ..., use utf8 encoding
 // Note that the appended... will also be calculated into the length
 $str = mb_strimwidth($str, 0, 10, '...', 'utf8');
}

// Finally output aaaa... 4 a's are counted as 4 1's, 2 are counted as 3 points, and 3 are counted as 4+2+3=9
// Isn't it very simple? Some people have said Why is it 9 and not 10?
// Because "Ah" happens to be followed by "Ah", Chinese counts 2, 9+2=11 exceeds the setting, so removing 1 is 9
echo $str;

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Let me introduce some other functions to you below:

mb_strlen($str, $encoding) returns the length of the string

$str The string to be calculated

$encoding The encoding used

mb_substr($str, $start, $length, $encoding) intercepts the string

$str The string to be intercepted

$start Where to start intercepting

$length How long to intercept

$encoding The encoding used

In fact, these two functions are very similar to strlen() and substr(). The only difference is that the encoding can be set.

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Example below:

/**
 * utf8 encoding format
 * 1 Chinese occupies 3 bytes
*/
$str = 'aa12ahaa';
echo strlen($str); // Direct output length is 9

// Output length is 7 , why is it 7?
// Note that after setting the encoding here, whether it is Chinese or English, the length of each is 1
// a a 1 2 ah a a
// 1+1+1+1+1+1+1 = 7
// Is it exactly 7 characters?
echo mb_strlen($str, 'utf8');

// The same is true for mb_substr
// I only want 5 characters now
echo mb_substr($str, 0, 5, 'utf8'); // Output aa12

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In fact, there are many useful functions in the mb extension, so I won’t list them all here.

Interested friends can check the official manual

http://www.php.net/manual/zh/ref.mbstring.php

Okay, that’s all for today.