有简单的方法可以从PHP中的多字节字符串中获取字符吗？

Question

This is my problem: My language (Portuguese) uses ISO-8859-1 char encoding! When I want access a character from a string like 'coração' (heart) I use:

mb_internal_encoding('ISO-8859-1');
$str = "coração";

$len = mb_strlen($str,'UTF-8');

for($i=0;$i<$len;++$i)
    echo mb_substr($str, $i, 1, 'UTF-8')."<br/>";

This produces:

c
o
r
a
ç
ã
o

This works fine... But my issue is if the use of mb_substr function is not fast as simple string normal access! But I want a simple way to do this.... like in normal string character access: echo $str[$pos].... It is possible?

Answer 1

mb_substr function is not fast as [...] like in normal string character access: echo $str[$pos].... It is possible?

No.

• The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!)
• Premature optimization

The multibyte functions have to check every character to determine how many bytes (1 to 4 in UTF-8) it occupies. There you immediately have the reason why character indexing ( $a[n] ) won't work: you don't know what byte(s) you need to get the n th character before you've read all characters before that one.

To speed things up a bit, you can look at the answers here: How to iterate UTF-8 string in PHP?

However, since you use ISO 8859-1 or Latin-1, you don't have to use the mb_ functions at all, since in that encoding all characters are encoded in one byte .

Answer 2

Try:

preg_match_all( "/./u", $str, $ar_chars );
print_r( $ar_chars ); 

Answer 3

... Sort of. If you use a fixed-width encoding (ISO 8859-*, UCS-2, or UTF-32, or UTF-16 within the BMP) then you can use a fixed multiplier for character accesses. You will still need to make multiple accesses for the multiple-byte encodings though.