PHP限制数组中每个字符串的长度 [英] PHP limit length of every string in array
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问题描述
我有一个包含多个字符串的数组,如下所示:
I have an array with multiple strings, like this:
$str[0] = "kasdnkjsandjabsdkjsbad";
$str[1] = "kasdnkjsandjasdjksabdjkasbkjdsak";
$str[2] = "kasdnkjsandsadbaskjdbsakjdbasdsadjsadjksabdk";
$str[3] = "kasdnkjsandasdjbaskdbjsakbdkjsabdjksabdkjsabdjkasbdjksa";
$str[4] = "kasdnkjsandsajdbaskjdbjksabdjkbasjkdbjksadbjksadbjksadbjksadbkjsa";
$str[5] = "kasdnkjsandasdjbsakdjbsakjdbsakjdsakjdbjksabdjksabdkjasbkjdasbkjdbsakjdsabjk";
假设我不知道某个数组中有多少个字符串,有什么办法可以限制所有数组的字符串长度.
Is there any way i can limit the string length of all arrays, assuming i don't know how many strings there will be in a certain array.
谢谢
推荐答案
从理论上讲,这很简单:只需创建一个将限制"字符串长度的函数,如果它太长,则将其剥离:
Well, theoretically, this is pretty simple: just create a function that will "limit" the length of the string, and if it's too long, strip it off:
<?php
$str = array( );
$str[0] = "kasdnkjsandjabsdkjsbad";
$str[1] = "kasdnkjsandjasdjksabdjkasbkjdsak";
$str[2] = "kasdnkjsandsadbaskjdbsakjdbasdsadjsadjksabdk";
$str[3] = "kasdnkjsandasdjbaskdbjsakbdkjsabdjksabdkjsabdjkasbdjksa";
$str[4] = "kasdnkjsandsajdbaskjdbjksabdjkbasjkdbjksadbjksadbjksadbjksadbkjsa";
$str[5] = "kasdnkjsandasdjbsakdjbsakjdbsakjdsakjdbjksabdjksabdkjasbkjdasbkjdbsakjdsabjk";
$length = 10;
$substr = function( $element ) use ( $length ) {
return substr( $element, 0, $length );
};
$str = array_map( $substr, $str );
var_dump( $str );
EDIT :如果要在将字符添加到数组时限制"字符数,则可以在函数中简单地创建一个检查:
EDIT: if you want to "limit" the number of characters while adding them to the array, you can simply create a check in a function:
<?php
function append( &$array, $value, $length = 25 ) {
if( mb_strlen( $value ) > $length ) {
return false;
}
return $array[] = $value;
}
$strings = array( );
append( $strings, 'kasdnkjsandjabsdkjsbad' ); // is accepted.
append( $strings, 'kasdnkjsandjabsdkjsbadkasdnkjs' ); // is not accepted
append( $strings, 'kasdnkjsandsadbaskjdbsakjdbasdsadjsadjksabdk' ); // is not accepted.
// if you *really* want to exit when a value is too long:
function append_exit( $array, $value, $length = 25 ) {
if( mb_strlen( $value ) > $length ) {
trigger_error( 'Value is too long.', E_USER_ERROR );
exit;
}
return $array[] = $value;
}
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