PHP string functions and array functions

/Verification Code
$str = "abcdefghijklmnopqrstuvwxyz0123456789";
$a =substr ($str, Rand (0,35), 1);
$b =substr ($str, Rand (0,35), 1);
$c =substr ($str, Rand (0,35), 1);
$d =substr ($str, Rand (0,35), 1);
echo $a. $b. $c. $d;

The length of the output string
$ABC = "Have you eaten?";
echo strlen ($ABC);

Splitting a string, dividing the array into groups
$ABC = "Gently I come, as I quietly walk, waving a wave of sleeves, not take away a cloud";
$arr =explode (",", $ABC);
$count =count ($arr); Look at the value after the split
Echo $count;
Print_r ($arr);

String connection
$arr =array (0=> "My Car",1=> "is the Red",2=> "BMW");
$abc =implode (",", $arr); Connect with commas in the middle
Echo $abc;

Uppercase and lowercase letters conversion
$str = "Adasdfjs";
$str =strtoupper ($STR); Convert all lowercase letters to uppercase
$str =ucfirst ($STR);//Convert first letter to uppercase
$str =strtolower ($STR); Convert all uppercase letters to lowercase letters
$str =ucfirst (Strtolower ($STR)); Converted to only the first letter is uppercase
Echo $str;

Convert HTML format to string format
$str = "<table width=200 border=1><tr><td> why people live </td></tr></table>";
$str =htmlspecialchars ($STR);
Header ("content-type:text/html;charset=gb2312"); Choose an encoding format
Echo $str;

Remove spaces
$ABC = "One must depend on oneself";
echo "People". RTrim (LTrim ($ABC)). " //rtrim is to remove the right space LTrim is to remove the left space, trim is to remove both sides of the space

View package contains no characters
$str = "I saw someone hanging a sheep's head in the street selling bombs";
$AA = "Bomb";
$num =substr_count ($str, $AA);
if ($num >0) {
echo "character contains illegal keywords";
}

See where a character appears
$STR = "I see the street, someone hangs a sheep's head in the street to sell bombs";
$AA = "Main Street";
$wz =strpos ($str, $AA); This is where the First Avenue appears.
$wz =strrpos ($str, $AA); This is where the last street came from.
Echo $wz;

Add removal \
$STR = "I see the street, someone in the street ' vinegar ' sell bombs";
$str =addcslashes ($str, "'");
Echo $str;

String padding
$str = "Dfsfs";
$str =str_pad ($str, ten, "V"); If the $str is not long enough, it will be automatically filled with V
Echo $str;

string comparison
$str 1= "AAAA";
$str 2= "AAAAAAA";
Echo strcmp ($str 1, $str 2);

All output from the location following the occurrence of the string
$str 1= "a";
$str 2= "DSFHFAVVVN";
Echo Strstr ($str 2, $str 1);

Replace character
$str 2= "DSFHFAVVVN";
$str =str_replace ("A", "B", $str 2); Case sensitive
$str =str_ireplace ("A", "B", $str 2); This substitution is case insensitive
$str =substr_replace ("A", "G", $str 2); The original value is only truncated a, plus g to form a new string
Echo $str;

Get address bar parameters, print an array

Parse_str ("id=5&cid=7", $myArray);
Print_r ($myArray);
Print_r ($_server); Get the server array

If the address bar has parameters, get the Address bar parameter and print the array
$str =$_server[' query_string '];
Parse_str ($str, $arr);
Print_r ($arr);

Output URL and Address bar parameters
$url = "Connection Address";

echo $url;
$arr =parse_url ($url);
Print_r ($arr);

Print array
$arr =array (0=> "My Car",1=> "is the Red",2=> "BMW");
Print_r ($arr);
echo $arr [1]; One of the values of the output array

See if there is a value in the array to find
$arr =array (0=> "BMW",1=> "Rolls-Royce",2=> "Mercedes");
$str = "BMW";
Echo In_array ($str, $arr); There is a return value of 1, there is no return value 0

To view the key values of an array
$arr =array (a=> "BMW",b=> "Rolls-Royce",c=> "Mercedes");
$str =array_keys ($arr);
Print_r ($STR);

Iterating through an array
$arr =array ("a" = "BMW", "b" = "Mercedes", "C" and "Rolls-Royce");
foreach ($arr as $key = = $value) {
Echo $key; Output key
echo $value. " <br> ";//Output key value
}

Current () function, next () function
$arr =array ("a" = "BMW", "b" = "Mercedes", "C" and "Rolls-Royce");
echo Key ($arr);
Echo current ($arr). "  <br> "; Returns the value of the array element with the current pointer position
Next ($arr);//Returns the value of the array element at the next position of the current pointer, moving the pointer down one
echo Key ($arr);
echo Key ($arr);

$arr =array ("a" = "BMW", "b" = "Mercedes", "C" and "Rolls-Royce");
$num =count ($arr);
for ($i =1; $i <= $num; $i + +) {
echo Key ($arr);
Echo current ($arr);
echo "<br>";
Next ($arr);
}

End () function, prev () function
$arr =array ("a" = "BMW", "b" = "Mercedes", "C" and "Rolls-Royce");
$num =count ($arr);
Echo End ($arr); Used to point the array pointer to the last element and return the value of the element
Prev ($arr); Returns an array element on the current pointer's previous position
Echo current ($arr);

Increase the value of an array element

Increase
$arr =array ("a" = "BMW", "b" = "Mercedes", "C" and "Rolls-Royce");
Array_push ($arr, "Audi", "Pentium"); Increase the value of an array element
Print_r ($arr);

$arr =array ("a" = "BMW", "b" = "Mercedes", "C" and "Rolls-Royce");
Array_unshift ($arr, "bubble face"); Used to add to the first element of an array
Print_r ($arr);

Array fill and remove repeating array elements
$arr =array ("a" = "BMW", "b" = "Mercedes", "C" and "Rolls-Royce");
$arr =array_pad ($arr, 10, "good");//array fill <br/>
$arr =array_unique ($arr); Remove duplicate elements from an array
Print_r ($arr);

Remove
$arr =array ("a" = "BMW", "b" = "Mercedes", "C" and "Rolls-Royce");
echo Array_pop ($arr); Remove the last element and reset the array
Print_r ($arr); The last array element is taken out

$arr =array ("a" = "BMW", "b" = "Mercedes", "C" and "Rolls-Royce");
for ($i =1; $i <=3; $i + +) {
echo Array_pop ($arr);
echo "<br>";
}

Ascending order ordering of array elements
$arr =array ("A", "D", "E", "C", "B");
Sort ($arr); Ascending
Rsort ($arr); The order
Print_r ($arr);

To synthesize multiple array groups into a new array
$arr =array ("A", "D", "E", "C", "B");
$arr 2=array ("K", "B", "N", "V", "U");
$arr =array_merge ($arr, $arr 2);//group to synthesize a new array
$arr =array_unique ($arr);//Remove duplicate elements from the new array
Sort ($arr); Sort Ascending
Print_r ($arr);

PHP string functions and array functions