PHP Learning Notes-string function exercises

Source: Internet
Author: User
Tags explode string splitter

1. Calculate the byte length function strlen ($STR)

$str= ' Hello world! ';       // Calculate byte length function strlen ($STR) Echo ' ' ',$str, ' The length is ',strlen($str), ' <br> ';

Output: "Hello world!" The length is 12

2. Calculate the character length function mb_strlen ($str, ' encoding (e.g. Utf-8) ')

$str 1= ' I am Chinese ';        // calculates the character length function Mb_strlen ($str, ' encoding (e.g. Utf-8) ') Echo ' ' ',$str 1, ' "', ' the number of bytes is ',strlen($str 1), ', the number of characters is ', Mb_strlen ($str 1, ' utf-8 '), ' < Br> ';

Output: "I am Chinese" the number of bytes is 15, the number of characters is 5

3. Determine the position of the substring in the string strpos ($str 1, $str), where $STR1 is a substring

$str 2= ' Hello world ';//determines the position of the substring in the string Strpos ($str 1, $str), where $STR1 is a substring$s= ' World ';if(($a=Strpos($str 2,$s))!==false){    Echo‘"‘,$s, ' ' ', ' in ',$str 2, ' The first of the ',$a, ' a position ';}Else{    Echo‘"‘,$s, ' ' ', ' does not exist ',$str 2, ' in ';}Echo' <br> ';

Output: "World" in the 6th position in "Hello World"

4. String substitution function str_replace ($str 1, $str 2, $str), where $str1 is the replaced string, $str 2 is the replaced string

$str 3= ' it\ ' s bullshit ';     // The string substitution function Str_replace ($str 1, $str 2, $str), where $str1 is the substituted string, $str 2 is the replaced string $str 4=str_replace(' bullshit ', ' * * ',$str 3); Echo ' "',$str 3, '" after substitution becomes "',$str 4, '" <br> ";

Output: "It's bullshit" replaced and became "it's * * *"

5. Replace a large number of String Strtr ($str, Array ())

$str 5= ' Some people live as if they were dead, some die but still live ';  // Replace a large number of strings STRTR ($STR, Array ()) $str 6=strtr($str 5,array// replace Live with dead, die replace alive echo ' "', $str 5, ' "replaced by" ',$str 6, ' "<br>";

Output: "Some people live as if they were dead, and some die and still live" replaced by "some people die as if they live, some live and still die."

6.substr ($str, $a, $b) intercepts the string, $a represents the position at which the Intercept begins, $b represents the Intercept length

$STR 7= ' My Pleasure,sir ';//substr ($str, $a, $b) intercepts the string, $a represents the position at which the Intercept begins, $b represents the Intercept lengthEcho substr($STR 7, 3,8), ' <br> '; Echo substr($STR 7, 2,8), ' <br> '; Echo substr($STR 7, 3), ' <br> ';//$b do not write, the default intercept to the lastEcho substr($STR 7, 3,-2), ' <br> ';//$b is negative, it will be truncated to the B-th characterEcho substr($STR 7, -3), ' <br> '; Echo substr($STR 7, -3,2), ' <br> ';//The $a is a negative number, and a is a representation of the inverse of a string positionEcho substr($STR 7, -3,-2), ' <br> ';//$a, $b are negative, both represent positions

Output Result:

Pleasure
Pleasur
Pleasure,sir
Pleasure,s
Sir
Si
S

7. The string splitter function explode ($s, $str) $s is a split node, and the result returns an array

$str 8= ' Hello, I am Chinese ';    // The string splitter function explode ($s, $str) $s is a split node, and the result returns an array Print_r (explode(', ',$str 8));

Output: Array ([0] = = Hello [1] = = I am Chinese)

8. The array is converted to a string function implode ($s, $arr)$arr is an array, $s is the associative node

$arr=array//implode ($s, $arr) $arr is an array, $s is the associative node echo  Implode(', ',$arr);

Output Result: Hello,world

PHP Learning Notes-string function exercises

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.