php - 如果字符串长于 50 封电子邮件，则将电子邮件字符串拆分为组

Question

有没有一种有效的方法可以将包含电子邮件地址列表的字符串拆分为 50 个组。假设我有一个包含逗号分隔格式的电子邮件的字符串。像... email1@host.com,email2@host.com,email3@host.com 等等。

最明显的方法可能是数组，但是有没有办法用字符串函数来做呢？我看过 substr 和 str_split ，他们似乎没有退出来完成这项工作。

谢谢

Answer 1

搜索第 50 次出现的逗号并在此之后拆分字符串应该更有效。所以找到这个职位。我认为这个http://www.php.net/manual/en/function.strpos.php#102336应该是一个解决方案。然后用 substr 拆分字符串并删除新字符串 pos 1 处的逗号。

缩短 PHP 代码以满足您的需求：

<?php 

function strnpos( $haystack, $needle, $nth, $offset = 0 ) { 
    //  If needle is not a string, it is converted to an integer and applied as the ordinal value of a character. 
    if(!is_string($needle)) 
        $needle = chr((int)$needle ); 

    //  Are the supplied values valid / reasonable? 
    $len = strlen( $needle ); 
    if(1 > $nth || 0 === $len) 
        return false; 

    //  $offset is incremented in the call to strpos, so make sure that the first 
    //  call starts at the right position by initially decreasing $offset by $len. 
    $offset -= $len; 
    do { 
        $offset = strpos( $haystack, $needle, $offset + $len ); 
    } while( --$nth  && false !== $offset ); 

    return $offset;
} 

$emails_str = 'email1@host.com,email2@host.com,email3@host.com,...';

$pos = strnpos($emails_str, ',', 50, 0);
while($pos) {
    // Do sth. with the group...
    echo substr($emails_str, 0, $pos), PHP_EOL; 

    // Cut this part out of the string
    $emails_str = substr($emails_str, $pos+1);
    $pos = strnpos($emails_str, ',', 50, 0);
}

Answer 2

是的，找到

$string="word_1, word_2, word_3"; 
$array=preg_split("/([,]{49}[,])+",$string);

或者你可以使用

一套完整的 strn*pos 函数，用于在大海捞针中寻找第 n 次出现的针。我更喜欢 strnpos 的这种实现，因为它在提供长度为 0 的针时不会给出可见的警告（诚然，这是非标准行为）。基于版本 I [最初发布于 2010 年 3 月 5 日]；这个新版本更符合 strpos 的语义。

<?php 

/** 
 *  This function implements all the strn*pos functions, which return the $nth occurrence of $needle 
 *  in $haystack, or false if it doesn't exist / when illegal parameters have been supplied. 
 * 
 *  @param  string  $haystack       the string to search in. 
 *  @param  MIXED   $needle         the string or the ASCII value of the character to search for. 
 *  @param  integer $nth            the number of the occurrence to look for. 
 *  @param  integer $offset         the position in $haystack to start looking for $needle. 
 *  @param  bool    $insensitive    should the function be case insensitive? 
 *  @param  bool    $reverse        should the function work its way backwards in the haystack? 
 *  @return MIXED   integer         either the position of the $nth occurrence of $needle in $haystack, 
 *               or boolean         false if it can't be found. 
 */ 
function strnripos_generic( $haystack, $needle, $nth, $offset, $insensitive, $reverse ) 
{ 
    //  If needle is not a string, it is converted to an integer and applied as the ordinal value of a character. 
    if( ! is_string( $needle ) ) { 
        $needle = chr( (int) $needle ); 
    } 

    //  Are the supplied values valid / reasonable? 
    $len = strlen( $needle ); 
    if( 1 > $nth || 0 === $len ) { 
        return false; 
    } 

    if( $insensitive ) { 
        $haystack = strtolower( $haystack ); 
        $needle   = strtolower( $needle   ); 
    } 

    if( $reverse ) { 
        $haystack = strrev( $haystack ); 
        $needle   = strrev( $needle   ); 
    } 

    //  $offset is incremented in the call to strpos, so make sure that the first 
    //  call starts at the right position by initially decreasing $offset by $len. 
    $offset -= $len; 
    do 
    { 
        $offset = strpos( $haystack, $needle, $offset + $len ); 
    } while( --$nth  && false !== $offset ); 

    return false === $offset || ! $reverse ? $offset : strlen( $haystack ) - $offset; 
} 

/** 
 *  @see    strnripos_generic 
 */ 
function strnpos( $haystack, $needle, $nth, $offset = 0 ) 
{ 
    return strnripos_generic( $haystack, $needle, $nth, $offset, false, false ); 
} 

/** 
 *  @see    strnripos_generic 
 */ 
function strnipos( $haystack, $needle, $nth, $offset = 0 ) 
{ 
    return strnripos_generic( $haystack, $needle, $nth, $offset, true, false ); 
} 

/** 
 *  @see    strnripos_generic 
 */ 
function strnrpos( $haystack, $needle, $nth, $offset = 0 ) 
{ 
    return strnripos_generic( $haystack, $needle, $nth, $offset, false, true ); 
} 

/** 
 *  @see    strnripos_generic 
 */ 
function strnripos( $haystack, $needle, $nth, $offset = 0 ) 
{ 
    return strnripos_generic( $haystack, $needle, $nth, $offset, true, true ); 
} 

$haystack = 'Dit is een HoTtentotTentenTentenToonstellingTest!'; 

echo strnpos  ( $haystack, 't', 5 ), ' === ', strnpos  ( $haystack, 116, 5 ), PHP_EOL; 
echo strnipos ( $haystack, 't', 5 ), ' === ', strnipos ( $haystack, 116, 5 ), PHP_EOL; 
echo strnrpos ( $haystack, 't', 5 ), ' === ', strnrpos ( $haystack, 116, 5 ), PHP_EOL; 
echo strnripos( $haystack, 't', 5 ), ' === ', strnripos( $haystack, 116, 5 ), PHP_EOL; 
echo PHP_EOL; 
echo strnpos  ( $haystack, 'T', 5 ), ' === ', strnpos  ( $haystack,  84, 5 ), PHP_EOL; 
echo strnipos ( $haystack, 'T', 5 ), ' === ', strnipos ( $haystack,  84, 5 ), PHP_EOL; 
echo strnrpos ( $haystack, 'T', 5 ), ' === ', strnrpos ( $haystack,  84, 5 ), PHP_EOL; 
echo strnripos( $haystack, 'T', 5 ), ' === ', strnripos( $haystack,  84, 5 ), PHP_EOL; 
?>

Answer 3

$emails = 'email1@host.com,email2@host.com,email3@host.com,...';
if( substr_count( $emails, '@' ) > 50 )
{
    $groups = explode( ',', $emails );
    $groups = array_chunk( $groups, 50 );

    $emails = '';
    foreach( $groups as $k => $group )
    {
        $group_data = implode( ', ', $group );
        $emails .= "{$group_data}<hr/>";
    }
}
echo $emails;