PHP common features, php_php tutorials

PHP Common features, PHP

1.PHP string

• The string declares the variable = ' ' or ' (the general case uses single quotes because it is easier to write)

$str = ' Hello PHP '; Echo $str;

• Strpos to calculate the position of a character in a string (starting at 0)

$str = ' Hello PHP '; Echo Strpos ($str, ' o ');  // calculates the position of a character in a string Echo '
'; Echo Strpos ($str, ' PH ');

• SUBSTR Intercept string

$str = ' Hello PHP '; // Intercept String $str 1 substr ($str// intercept from 2 position, intercept string with length 3 echo$str 1;

If the length parameter is not passed, it will be truncated from the specified position to the end of the string.

• Str_split split string fixed-length split (default length is 1)

$str = ' Hello PHP '; // Split String $result Str_split ($str);   // Save the result in an array Print_r ($result);  // enter an array using Print_r Echo '
'; $result 1 Str_split ($str, 2); Print_r ($result 1);

• Explode (split character, string to be split) separated by space

$str = ' Hello PHP Java C # C # '; $result Explode (',$str); Print_r ($result);

• Connection of strings

$str = ' Hello PHP Java C # C # '; // Connection of Strings $num = +; $str 1 $str. '
Objective-c '. $num ; Echo $str 1 ; Echo '
'; $str 2 = "$str
$num";    // another easy way to do it Echo $str 2;

2.PHP arrays

• Array declaration PHP arrays are very dynamic and can store all types of data

// how arrays are declared $arr Array (); $arr [0] = ' Hello '; $arr [1] = ' world '; $arr [2] = 2; $arr [3] = 3.14; Print_r ($arr);

• Array_push ()//Add an element
• Array_pop ()//delete last element

$arr Array ();  for ($i= 0; $i<100; $i+ +)    {array_push($arr, ' Item ').  $i);} Print_r ($arr);

• Storing data by key-value pairs (key-value)

$arr Array (); $arr [' H '] = ' Hello '; $arr [' W '] = ' world '; Print_r ($arr); Echo '
'; Echo $arr [' H '];

Output: Array ([H] = = Hello [W] = world) Hello

• Not only can the PHP array be used as an array, but also can be used as a map
• Array initialization

$arr Array (' H ' = ' Hello ', ' W ' = ' world ');    // Initialization of PHP arrays Print_r ($arr);

• You can have array markers at the same time, and key-value pairs

$arr Array (0=> ' make ',1=> ' Tom ', ' H ' = ' Hello ', ' W ' = ' ' World '); Print_r ($arr); Echo '
'; Echo $arr [0]; Echo '
'; Echo $arr [' W '];

Output: Array ([0] = make [1] = Tom [H] = = Hello [W] = World

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