Several applications of the PHPsubstr () function _ PHP Tutorial

Several program applications of the PHPsubstr () function. The substr () function describes part of the string returned by the substr () function. Syntax: substr (string, start, length ). String: required. Specifies that a part of the string is to be returned. Start: required substr () function introduction

The substr () function returns part of the string.

Syntax: substr (string, start, length ).

• String: required. Specifies that a part of the string is to be returned.
• Start: required. Specifies where the string starts. Positive value: start at the specified position of the string; negative value: start at the specified position from the end of the string; 0: start at the first character of the string.
• Charlist: Optional. Specifies the length of the string to be returned. The default value is until the end of the string. Positive number: return from the position where the start parameter is located; negative number: return from the end of the string.

Note: If start is a negative number and the length is less than or equal to start, the length is 0.

Program List: The start parameter of a negative value.

 ';$rest = substr("abcdef", -2);    // returns "ef"echo $rest.'
';$rest = substr("abcdef", -3, 1); // returns "d"echo $rest.'
';?>

Program running result:

fefd

Program List: length parameter of a negative value

Start from the start position. if the length is negative, it starts from the end of the string. Substr ("abcdef", 2,-1), that is, starting from c, and then-1 indicates intercepting to e, that is, intercepting cde.

    
 ';$rest = substr("abcdef", 2, -1);  // returns "cde"echo $rest.'
';$rest = substr("abcdef", 4, -4);  // returns ""echo $rest.'
';$rest = substr("abcdef", -3, -1); // returns "de"echo $rest.'
';?>

Program running result:

abcdecdede

Program List: basic substr () function usage

 ';echo substr('abcdef', 1, 3);  // bcdecho '
';echo substr('abcdef', 0, 4);  // abcdecho '
';echo substr('abcdef', 0, 8);  // abcdefecho '
';echo substr('abcdef', -1, 1); // fecho '
';// Accessing single characters in a string// can also be achieved using "square brackets"$string = 'abcdef';echo $string[0];                 // aecho '
';echo $string[3];                 // decho '
';echo $string[strlen($string)-1]; // fecho '
';?>

Program running result:

bcdefbcdabcdabcdeffadf

Program List: remove suffix

Program running result:

bkjia.jpg

Program List: a string that is too long is displayed only at the beginning and end. it is replaced by a ellipsis in the middle.

 30) {$ vartypesf = strrchr ($ file ,". "); // get the total length of the character $ vartypesf_len = strlen ($ vartypesf); // extract the 15 characters on the left $ word_l_w = substr ($ file ); // capture 15 characters on the right $ word_r_w = substr ($ file,-15); $ word_r_a = substr ($ word_r_w, 0,-$ vartypesf_len); return $ word_l_w. "... ". $ word_r_a. $ vartypesf;} else return $ file;} // RETURN: hellothisfileha..andthisfayl.exe $ result = funclongwords ($ file); echo $ result;?>

Program running result:

Hellothisfileha...andthisfayl.exe

Program List: displays more text as ellipsis

In many cases, we need to display a fixed number of words, and the extra words should be replaced by ellipsis.

    
  $length)   return (preg_match('/^(.*)\W.*$/', substr($string, 0, $length+1), $matches) ? $matches[1] : substr($string, 0, $length)) . $replacer;     return $string; } ?>

Program running result:

welcome to bkjia, I hope...

Program List: format a string

Sometimes we need to format strings, such as phone numbers.

  
 = $FormatPos){        //If its a number => stores it        if (is_numeric(substr($Format, $FormatPos, 1))){            $Result .= substr($String, $StringPos, 1);            $StringPos++;        //If it is not a number => stores the caracter        } else {            $Result .= substr($Format, $FormatPos, 1);        }        //Next caracter at the mask.        $FormatPos++;    }    return $Result;}// For phone numbers at Buenos Aires, Argentina// Example 1:    $String = "8607562337788";    $Format = "+00 0000 0000000";    echo str_format_number($String, $Format); echo '
';// Example 2:    $String = "8607562337788";    $Format = "+00 0000 00.0000000";    echo str_format_number($String, $Format); echo '
';// Example 3:    $String = "8607562337788";    $Format = "+00 0000 00.000 a";    echo str_format_number($String, $Format); echo '
';?>

Program running result:

+86 0756 2337788+86 0756 23.37788+86 0756 23.377 a

The http://www.bkjia.com/PHPjc/752408.htmlwww.bkjia.comtruehttp://www.bkjia.com/PHPjc/752408.htmlTechArticlesubstr () function introduces the substr () function to return part of a string. Syntax: substr (string, start, length ). String: required. Specifies that a part of the string is to be returned. Start: required...