PHP Regular Expressions and arrays

First, regular expression

1. "/" stands for delimiters, "^" stands for the starting symbol, "$" for the end symbol

$str 1= "Abc123def45ghjk6789lou";

$str 2= "ABCDE5FG2H6JKL";

$reg = "/\d/"; Match a number

2. Echo preg_replace ($reg, "#", $str 1); Replace the string str1 with the regular expression Reg #

Output: abc## #def # #ghjk## # # # # ##lou

3. Var_dump (preg_split ($reg, $str 2)); The string str2 is split according to the regular expression Reg, returning an array

Output: Array (4) {[0]=> string (5) "ABCDE" [1]=> string (2) "FG" [2]=> string (1) "H" [3]=> string (3) "JKL"}

4. $str = "Pick Me up Oh Alice 18953364666 Crazy Group of calligraphy 13,853,369,999 poor odd ah";

$reg = "/(13[0-9]|14[5|7]|15[0|1|2|3|5|6|7|8| 9]|170[0|5|7|8|   9]|17[6|7|8]|18[0-9]) \d{8}/"; Mobile phone number Regular expression

$arr =array ();

Preg_match ($reg, $str, $arr); Matches the first data in a string that satisfies a regular expression

Var_dump ($arr);

Preg_match_all ($reg, $str, $arr); // match all data in a string that satisfies a regular expression

Var_dump ($arr);

Second, array

1. Define the array:

Mode one: Standard array definition

$arr =array (1,2,3,4,5);

Method Two: Assignment definition:

$arr [0]=5;

$arr [1]=6;

Var_dump ($arr);

2. Classification:

2.1 Index Array: Writes only value values in an array, indexes are automatically generated, and values are based on indexed numbers

$arr =array (1,2,3,4,5);

echo $arr [0];

2.2 Associative array: key = Value,key corresponds to value one by one, paired existence

$arr = ("one"= 5, "One"and "10");

Echo $arr ["both"];

Note: Associative array relationships are clearer, key and value must be written in full

PHP Array Features: Can store any type of data, the length can vary, special about the associated array

3. Iterating through an array

3.1 for loop traversal: cannot traverse associative array

$arr =array ("AA", "BB", "CC", 5, "D", 10);

$arr =array ("A" =>10, "B" =>5, "c" = "Hello", "D" =>20);

for ($i =0; $i <count ($arr); $i + +)

{

echo $arr [$i]. " <br> ";

}

3.2 foreach traversal: can traverse associative arrays

Take value only:

foreach ($arr as $value)

{

echo $value. " <br> ";

}

Take key and value:

foreach ($arr as $key = $value)

{

echo $key. " --". $value." <br> ";

}

3.3 each () function

Var_dump (each ($arr)); Returns the key and value of the element inside the array

Var_dump (each ($arr)); Go down one at a time, point to the next value

Equivalent to a pointer, first time value, pointer to first element, second fetch, pointer to second element

3.4 list () function is special and appears on the left side of the equals sign

List ($a, $b, $c) = $arr; Assign the values inside the array to the variables in the list function, but the variables can be less, but not more

echo $a; Output: AA

Each () and list () are combined to iterate through the array: can traverse associative arrays

while (list ($key, $value) =each ($arr))

{

echo "{$key}--{$value}<br>";

}

3.5 pointer traversal: can traverse associative array

Var_dump (current($arr)); Value that points to the position of the current pointer

echo Key ($arr); Key that points to the position of the current pointer

Next ($arr); //Adjust the pointer to

echo $key ($arr);

prev ($arr); //Raise the pointer upward

End ($arr); //Adjust the pointer to the last

Reset ($arr); Resets the pointer, pointing to the first

do{

echo Key ($arr). " --". Current ($arr)." <br> ";

}

while (Next ($arr))

while (Next ($arr))

do{

echo Key ($arr). " --". Current ($arr)." <br> ";

}

Next () is executed first, and the first element is not taken.

4. Pre-defined arrays

Global//declared as Globals

$GLOBALS//referencing global variables available in global scope

Var_dump ($_server); Server and execution Environment information

Var_dump ($_ENV); Environment variables

Var_dump ($_get); HTTP get variable stores the value that the page passes over

Var_dump ($_post); The HTTP post variable stores the value that the page passes over

$_request//http REQUEST Variable

$_files//http FILES variables

$_session//session Variable

$_cookie//http Cookies

5. Common functions of arrays

$arr =array ("AA", "BB", "CC", 5, "D", 10);

$arr =array ("A" =>10, "B" =>5, "c" = "Hello", "D" =>20);

Var_dump (in_array ("AA", $arr)); Determines if there is a value in the array, returns true if it exists, or false to determine the value in the associative array, and cannot determine the key

Var_dump (array_reverse ($arr)); Flipping an array

Echo count ($arr); Returns the number of array elements

$attr =Array_unique ($arr); To return a new array, and if it is an indexed array, the index of the repeating element is also removed

unset ($arr [0]); | |unset ($arr ["a"]); Deletes an element in an array, depending on the index or key

Var_dump (array_values ($attr)); Re-index, key in associative array also becomes index

$attr = (1,2,3,4);

Var_dump (array_merge ($arr, $attr)); Merge arrays, re-index, associative array key invariant

Array_push ($arr, "DD"); Appends an element to an array to become the last element of the array

6. Two-dimensional array

$attr =array (

Array (+/-),

Array (4,5,6),

Array (7,8,9)

);

Var_dump ($ATTR);

Example 1:

$attr =array (

Array ("n001", "Han"),

Array ("n002", "Miao"),

Array ("n003", "Hui"),

Array ("n004", "Uighur")

);

1.1 Displays the contents of the two-dimensional array in the form of a drop-down list:

echo "<select>";

foreach ($attr as $value)

{

echo "<option value= ' {$value [0]} ' >{$value [1]}</option>";

}

echo "</select>";

1.2 Displays the contents of the two-dimensional array as a div:

<style>

. minzu{width=100px; background-color:red; color:white; border:1px solid;}

</style>

<body>

<?php

foreach ($attr as $v)

{

echo "<div class= ' Minzu ' >{$v [0]},{$v [1]}</div>";

}

?>

Example 2:

$attr = Array (
Array (' P001 ', ' Zhang San ', ' Male ', ' Han '),
Array (' P002 ', ' John Doe ', ' female ', ' hui '),
Array (' P003 ', ' Harry ', ' Male ', ' Han '),
Array (' p004 ', ' Zhao Liu ', ' female ', ' Miao ')
);

2.1 Displaying the contents of a two-dimensional array in a tabular format

echo "<table width= ' border= ' 1 ' cellpadding= ' 0 ' cellspacing= ' 0 ' >";

echo "<tr><td> code </td><td> name </td><td> Gender </td><td> National </td> </tr> ";

for ($i =0; $i <count ($attr); $i + +)

{

echo "<tr><td>{$attr [$i][0]}</td><td>{$attr [$i][1]}</td><td>{$attr [$i][2]} </td><td>{$attr [$i][3]}</td></tr>];

}

echo "</table>";

2.2 or reference the PHP code in the table:

<table width= ' border= ' 1 ' cellpadding= ' 0 ' cellspacing= ' 0 ' >

<tr><td> Code </td><td> name </td><td> Gender </td><td> National </TD></TR >

<?php

for ($i =0; $i <count ($attr); $i + +)

{

echo "<tr>

<td>{$attr [$i][0]}</td>

<td>{$attr [$i][1]}</td>

<td>{$attr [$i][2]}</td>

<td>{$attr [$i][3]}</td>

</tr> ";

}

?>

</table>

PHP Regular Expressions and arrays