PHP Array Learning_PHP Tutorial

Today I learned about arrays, which can be said to be the most important method in PHP data applications. There are many array functions in PHP. The following is a summary of what I learned. I will write it down for future reference...
1. Array definition:
The definition of an array is defined using the array() method. , you can define an empty array:

Copy code The code is as follows:

$number = array( 1,3,5,7,9);
//Define empty array
$result = array();
$color =array("red","blue","green");
//Custom key value
$language = (1=>"English",3=>"Chinese",5=>"Franch");
//Define a two-dimensional array
$two = array(
"color"=>array("red","blue"), //End with comma
"week"=>array("Monday","Friday ") //The last sentence has no punctuation
);
?>

2. Create an array:
The functions included in creating an array include compact( )、 >

Copy code

The code is as follows: $number = "1,3,5,7,9";

$string = "I'm PHPer";

$array = array("And","You?");
$newArray = compact("number","string","array") ;
print_r ($newArray);
?>


compact() function is used to convert two or more variables into arrays, including array variables of course. The parameter is the name of the variable rather than the full name with $.
　　　The opposite function is extract(). As the name suggests, it converts the array into a single string, with the key value as its string name and the array value as the string value.
Running results:

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The code is as follows: Array ( [number] => 1,3, 5,7,9 [string] => I'm PHPer [array] => Array ( [0] => And [1] => You? ) )

2 .array_combine()——Reorganize two arrays into one array, one as the key value and the other as the value:
　array array_combine ( array $keys , array $values ​​)

Copy the code

The code is as follows: $number = array("1","3","5","7","9 ");

$array = array("I","Am","A","PHP","er");

$newArray = array_combine($number,$array);
print_r ($newArray);
?>


I won’t go into detail about the array_combine function, everyone will understand it after reading it
Running results:

Array ( [1] => I [3] => Am [5] => A [7] => PHP [9] => er )
　3.range() function - Create an array within a specified range:
　　　　　　　　　　　　　　　　　　


Copy code

The code is as follows:

$array1 = range(0,100,10);//0 is the starting value, 100 is the end value, and 10 is the step value (the default step value is 1). print_r($array1);

echo "
";

$array2 = range("A","Z");
print_r($array2);
echo "
";
$array3 = range("z","a");
print_r($array3);
?>


Default step value of range() function It’s 1!
Running results:

Copy code

The code is as follows:

Array ( [0] => 0 [1] => 10 [2] => 20 [3] => 30 [4] => 40 [5] => 50 [6] => 60 [7] => 70 [8] => 80 [9] => 90 [10] => 100 )
Array ( [0] => A [1] => B [2] => C [3] => D [4] => E [5] => F [6] => G [7] => H [8] => I [9] => J [10] => K [11] => L [12] => M [13] => N [14] => O [15] => P [16] => Q [17] => R [18] => S [19] => T [20] => U [21] => V [22] => W [23] => X [24] => Y [25] => Z )
Array ( [0] => z [1] => y [2] => x [3] => w [4] => v [5] => u [6] => t [7] => s [8] => r [9] => q [10] => p [11] => o [12] => n [13] => m [14] => l [15] => k [16] => j [17] => i [18] => h [19] => g [20] => f [21] => e [22] => d [23] => c [24] => b [25] => a )

4.array_fill()函数——填充数组函数：

复制代码 代码如下:

$array = range(1,10);
$fillarray = range("a","d");
$arrayFilled = array_fill(0,5,$fillarray);//这里的$fillarray可以是字符串，如"test".
echo "

"; <br>print_r ($arrayFilled); <br>echo "

";
$keys = array("string","2",9,"SDK","PK");
$array2 = array_fill_keys($keys,"testing");
echo "

"; <br>print_r ($array2); <br>echo "

";
?>

运行结果：

复制代码 代码如下:

Array
(
[0] => Array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
[1] => Array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
[2] => Array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
[3] => Array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
[4] => Array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
)
Array
(
[string] => testing
[2] => testing
[9] => testing
[SDK] => testing
[PK] => testing
)

二、数组的遍历：
　　　　1.foreach遍历：
　　　　　　　foreach (array_expression as $value){}
　　　　　　　foreach (array_expression as $key => $value){}
　　　　　　闲话少说，上实例：

复制代码 代码如下:

$speed = array(50,120,180,240,380);
foreach($speed as $keys=>$values){
echo $keys."=>".$values."
";
}
?>

运行结果：

复制代码 代码如下:

0=>50
1=>120
2=>180
3=>240
4=>380

2.while循环遍历：
　　　　　　while循环遍历一般结合list函数，以下是实例

复制代码 代码如下:

$staff = array(
array("姓名","性别","年龄"),
array("小张","男",24),
array("小王","女",25),
array("小李","男",23)
);
echo "";
while(list($keys,$value) = each($staff)){
list($name,$sex,$age) = $value;
echo "";
}
echo "

$name

$sex

$age

";
?>

运行结果：

姓名	性别	年龄
小张	男	24
小王	女	25
小李	男	23

3. The for loop traverses:

Copy code The code is as follows:

$speed = range( 0,220,20);
for($i =0;$iecho $speed[$i]." ";
}
? >

Run result:

Copy code The code is as follows:

0 20 40 60 80 100 120 140 160 180 200 220

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