Php 简明教程

chmod 755 xampp-linux-*-installer.run

sudo ./xampp-linux-*-installer.run

sudo /opt/lampp/lampp start

Starting XAMPP ...
LAMPP: Starting Apache...
LAMPP: Starting MySQL...
LAMPP started.
Ready. Apache and MySQL are running.

cd /opt/lampp
sudo ./manager-linux.run (or manager-linux-x64.run)

sudo /opt/lampp/lampp stop

Stopping XAMPP ...
LAMPP: Stopping Apache...
LAMPP: Stopping MySQL...
LAMPP stopped.

cd /opt/lampp
sudo ./manager-linux.run (or manager-linux-x64.run)

http://127.0.0.1/info.php

<?php
   One or more PHP statements
?>

<?php
	One or more PHP statements
?>

short_open_tag=on

<%...%>

<script language = "PHP">...</script>

<p>This is a HTML statement</p>
<?php echo This is a PHP statement.'; ?>
<p>This is another HTML statement.</p>

<?php if ($expression == true): ?>
   This HTML statement will be rendered.
<?php else: ?>
   Otherwise this HTML statement will be rendered.
<?php endif; ?>

<?php
   echo "Hello PHP!!!!!";
?>

C:\xampp\htdocs>php hello.php

Hello PHP!!!!!

<?php
   $x = 10;
   echo "Data type of x: " . gettype($x) . "\n";

   $x = 10.55;
   echo "Data type of x now: " . gettype($x) . "";
?>

Data type of x: integer
Data type of x now: double

<?php
   $x = 10;
   $y = "20";

   echo "x + y is: ", $x+$y;
?>

x + y is: 30

<?php
   $x = 10;
   $y = 20;
   $z = $x+$y;
   echo "(before) z = ". $z . "\n";

   $y=5;
   echo "(after) z = ". $z . "";
?>

(before) z = 30
(after) z = 30

<?php
   $x = 10;
   $y = &$x;
   $z = $x+$y;
   echo "x=". $x . " y=" . $y . " z = ". $z . "\n";

   $y=20;
   $z = $x+$y;
   echo "x=". $x . " y=" . $y . " z = ". $z . "";
?>

x=10 y=10 z = 20
x=20 y=20 z = 40

echo(string ...$expressions): void

print(string $expression): int

<?php
   $x = 10;
   var_dump ($x);
?>

int(10)

<?php
   $x = 10.25;
   var_dump ($x);
?>

float(10.25)

<?php
   $x = true;
   var_dump ($x);
?>

bool(true)

<?php
   $x = "Hello World";
   var_dump ($x);
?>

string(11) "Hello World"

<?php
   echo "<pre>";
   $x = "Hello World";
   var_dump ($x);
   echo "</pre>"
?>

string(11) "Hello World"

<?php
   $x = array("Hello", false, 99.99, array(10, 20,30));
   var_dump ($x);
?>

array(4) {
  [0]=>
  string(5) "Hello"
  [1]=>
  bool(false)
  [2]=>
  float(99.99)
  [3]=>
  array(3) {
    [0]=>
    int(10)
    [1]=>
    int(20)
    [2]=>
    int(30)
  }
}

<?php
   $x = array(
      "Hello", false, 99.99,
      array(1=>10, 2=>20,3=>30)
   );
   var_dump($x);
?>

array(4) {
  [0]=>
  string(5) "Hello"
  [1]=>
  bool(false)
  [2]=>
  float(99.99)
  [3]=>
  array(3) {
    [1]=>
    int(10)
    [2]=>
    int(20)
    [3]=>
    int(30)
  }
}

<?php
   class Point {
      private int $x;
      private int $y;

      public function __construct(int $x, int $y = 0) {
         $this->x = $x;
         $this->y = $y;
      }
   }

   $p = new Point(4, 5);
   var_dump($p)
?>

object(Point)#1 (2) {
  ["x":"Point":private]=>
  int(4)
  ["y":"Point":private]=>
  int(5)
}

var_dump(get_defined_vars());

<?php
   $a = 'good';
   $$a = 'morning';

   echo "$a {$$a}\n";
   echo "$a $good";
?>

good morning
good morning

<?php
   $x = "foo";
   $$x = "bar";
   echo "Value of x = " .$x . "\n";
   echo 'Value of $$x = ' . $$x . "\n";
   echo 'Value of foo = ' . $foo;
?>

Value of x = foo
Value of $$x = bar
Value of foo = bar

// Valid constant names
define("ONE",     "first thing");
define("TWO2",    "second thing");
define("THREE_3", "third thing");
define("__THREE__", "third value");

// Invalid constant names
define("2TWO",    "second thing");

define(string $const_name, mixed $value, bool $case = false): bool

constant(string $name): mixed

<?php
   define("MINSIZE", 50);

   echo MINSIZE;
   echo PHP_EOL;
   echo constant("MINSIZE");	// same thing as the previous line
?>

50
50

<?php
   define('MAX', 100);

   if (defined('MAX')) {
      echo MAX;
   }
?>

100

<?php
   $x="Hello World";
   echo "$x. The current Line number is " . __LINE__ . ".";
?>

Hello World. The current Line number is 5.

<?php
   $x="Hello World";
   echo "$x. Current PHP script name is " . __FILE__ . ".";
?>

Hello World. Current PHP script name is C:\xampp\htdocs\hello.php.

<?php
   $x="Hello World";
   echo "$x. Directory of the Current PHP script name is " . __DIR__ . ".";
?>

Hello World. Directory of the Current PHP script name is C:\xampp\htdocs.

<?php
   function hello(){
      $x="Hello World";
      echo "$x. The function name is ". __FUNCTION__ . "";
   }
   hello();
?>

Hello World. The function name is hello

<?php
   class myclass {
      public function __construct() {
         echo "Inside the constructor of ". __CLASS__ . PHP_EOL;
      }
      function getClassName(){
         echo "from an instance method of " . __CLASS__ . "";
      }
   }
   $obj = new myclass;
   $obj->getClassName();
?>

Inside the constructor of myclass
from an instance method of myclass

<?php
   class myclass {
      public function __construct() {
         echo "Calling " . __METHOD__ . " of " . __CLASS__ ."<br>";
      }
      function mymethod(){
         echo "Calling " . __METHOD__ . " of " . __CLASS__ ."";
      }
   }
   $obj = new myclass;
   $obj->mymethod();
?>

Calling myclass::__construct of myclass
Calling myclass::mymethod of myclass

<?php
   trait mytrait {
      public function hello() {
         echo "Hello World from " . __TRAIT__ ."";
      }
   }
   class myclass {
      use mytrait;
   }
   $obj = new myclass();
   $obj->hello();
?>

Hello World from mytrait

<?php
   namespace myspace;
   class myclass {
      public function __construct() {
         echo "Name of the class: " . __CLASS__ . " in " . __NAMESPACE__ . "";
      }
   }
   $class_name = __NAMESPACE__ . '\myclass';
   $a = new $class_name;
?>

Name of the class: myspace\myclass in myspace

<?php
   namespace myspace;
   class myclass {
      public function __construct() {
         echo "Name of the class: " . myclass::class ;
      }
   }
   use myspace;
   $a = new myclass;
?>

Name of the class: myspace\myclass

$int_var = 12345;
$another_int = -12345 + 12345;

$var1 = 1.55
$var2 =-123.0

− 1.2e3, 2.33e-4, 7E-10, 1.0E5

<?php
   $many = 2.2888800;
   $many_2 = 2.2111200;
   $few = $many + $many_2;

   print("$many + $many_2 = $few");
?>

2.28888 + 2.21112 = 4.5

$bool1 = true;
$bool2 = false;

$bool3 = 1;
$bool4 = 0;

if (TRUE)
   print("This will always print.");

else
   print("This will never print.");

$string_1 = "This is a string in double quotes";
$string_2 = 'This is a somewhat longer, singly quoted string';

$string_39 = "This string has thirty-nine characters";
$string_0 = "";		// a string with zero characters

<?php
   $variable = "name";
   $literally = 'My $variable will not print!';

   print($literally);
   print "\n";

   $literally = "My $variable will print!";
   print($literally);
?>

My $variable will not print!
My name will print

$my_var = NULL;

$my_var = null;

class foo {
   function bar() {
      echo "Hello World.";
   }
}
$obj = new foo;
$obj->bar();

$fp = fopen("foo.txt", "w");

<?php
   $x = 10;
   echo gettype($x) . "\n";

   $y = 10.55;
   echo gettype($y) . "\n";

   $z = [1,2,3,4,5];
   echo gettype($z);
?>

integer
double
array

<?php
   $a = 10;
   $b = '20';
   $c = $a+$b;
   echo "c = " . $c;
?>

c = 30

<?php
   $a = 10;
   $b = '20';
   $c = $a.$b;
   echo "c = " . $c;
?>

c = 1020

$var = (type)expr;

<?php
   $a = 9.99;
   $b = (int)$a;
   var_dump($b);
?>

int(9)

<?php
   $a = 100;
   $b = (double)$a;
   var_dump($b);
?>

float(100)

<?php
   $a = "100";
   $b = (double)$a;
   var_dump($b);

   $a = "9.99";
   $b = (float)$a;
   var_dump($b);
?>

float(100)
float(9.99)

<?php
   $a = "1.23E01";
   $b = (double)$a;
   var_dump($b);
   $a = "5.5E-5";
   $b = (float)$a;
   var_dump($b);
?>

float(12.3)
float(5.5E-5)

<?php
   $a = "295.95 only";
   $b = (double)$a;
   var_dump($b);

   $a = "$2.50";
   $b = (float)$a;
   var_dump($b);
?>

float(295.95)
float(0)

<?php
   $a = 100;
   $b = (string)$a;
   var_dump($b);

   $x = 55.50;
   $y = (string)$x;
   var_dump($y);
?>

string(3) "100"
string(4) "55.5"

<?php
   $a = 100;
   $b = (bool)$a;

   $x = 0;
   $y = (bool)$x;

   $m = "Hello";
   $n = (bool)$m;

   var_dump($b);
   var_dump($y);
   var_dump($n);
?>

bool(true)
bool(false)
bool(true)

<?php
   $var = "Hello";
   echo "The variable \$var is of " . gettype($var) . " type" .PHP_EOL;

   $var = 10;
   echo "The variable \$var is of " . gettype($var) . " type" .PHP_EOL;

   $var = true;
   echo "The variable \$var is of " . gettype($var) . " type" .PHP_EOL;

   $var = [1,2,3,4];
   echo "The variable \$var is of " . gettype($var) . " type" .PHP_EOL;
?>

The variable $var is of string type
The variable $var is of integer type
The variable $var is of boolean type
The variable $var is of array type

<?php
   $var1=100;
   $var2="100";
   $var3=$var1+$var2;
   var_dump($var3);
?>

int(200)

<?php
   $var1=100;
   $var2="100 days";
   $var3=$var1+$var2;
   var_dump($var3);
?>

int(200)

PHP Warning:  A non-numeric value encountered in /home/cg/root/53040/main.php on line 4

$str = 'this is a simple string';

$str = "this is a simple string";

<?php
   $str = "\120\110\120";
   echo "PHP with Octal: ". $str;
   echo PHP_EOL;

   $str = "\x50\x48\x50";
   echo "PHP with Hexadecimal: ". $str;
?>

PHP with Octal: PHP
PHP with Hexadecimal: PHP

<?php
   $string1="Hello World";
   $string2="1234";

   echo $string1 . " " . $string2;
?>

Hello World 1234

<?php
   $gender="Male";
   var_dump ($gender=="Male");
?>

bool(true)

$mark=60;

if ($mark>50)
   echo "pass";
else
   echo "fail";

<?php
   $a = 1234;
   echo "1234 is an Integer in decimal notation: $a\n";

   $b = 0123;
   echo "0o123 is an integer in Octal notation: $b\n";

   $c = 0x1A;
   echo "0xaA is an integer in Hexadecimal notation: $c\n";

   $d = 0b1111;
   echo "0b1111 is an integer in binary notation: $d\n";
?>

1234 is an Integer in decimal notation: 1234
0o123 is an integer in Octal notation: 83
0xaA is an integer in Hexadecimal notation: 26
0b1111 is an integer in binary notation: 15

<?php
   $a = 1_234_567;
   echo "1_234_567 is an Integer with _ as separator: $a\n";
?>

1_234_567 is an Integer with _ as separator: 1234567

<?php
   $x = 1000000;
   $y =  50000000000000 * $x;
   var_dump($y);
?>

float(5.0E+19)

<?php
   $x = 10;
   $y = 3.5;
   $z = $x/$y;
   var_dump ($z);
   $z = intdiv($x, $y);
   var_dump ($z);
?>

float(2.857142857142857)
int(3)

<?php
   $a = 1234;
   echo "1234 is an Integer in decimal notation: $a\n";

   $b = 0123;
   echo "0o123 is an integer in Octal notation: $b\n";

   $c = 0x1A;
   echo "0xaA is an integer in Hexadecimal notation: $c\n";

   $d = 0b1111;
   echo "0b1111 is an integer in binary notation: $d";
?>

1234 is an Integer in decimal notation: 1234
0o123 is an integer in Octal notation: 83
0xaA is an integer in Hexadecimal notation: 26
0b1111 is an integer in binary notation: 15

<?php
   $a = 1_234_567;
   echo "1_234_567 is an Integer with _ as separator: $a";
?>

1_234_567 is an Integer with _ as separator: 1234567

<?php
   $x = 1000000;
   $y =  50000000000000 * $x;
   var_dump($y);
?>

float(5.0E+19)

<?php
   $x = 10;
   $y = 3.5;
   $z = $x/$y;
   var_dump ($z);
   $z = intdiv($x, $y);
   var_dump ($z);
?>

float(2.857142857142857)
int(3)

abs( mixed $num)

ceil ( float $num ) : float

exp ( float $arg ) : float

floor ( float $num ) : float

x = y*i+r

intdiv ( int $x , int $y ) : int

log10x=logex/loge10 ; So that
log10100=loge100/loge10 = 2

log10 ( float $arg ) : float

max ( array $values ) : mixed

max ( mixed $value1 [, mixed $... ] ) : mixed

min ( array $values ) : mixed

min ( mixed $value1 [, mixed $... ] ) : mixed

pow ( number $base , number $exp ) : number

round ( float $value , int $precision , int $mode ) : float

sqrt (float $arg) : float

<?php
   $lang="PHP";

   $str = <<<'IDENTIFIER'
   This is an example of Nowdoc string.
   it can span multiple lines
   and include single quote ' and double quotes "
   IT doesn't expand the value of $lang variable
   IDENTIFIER;

   echo $str;
?>

This is an example of Nowdoc string.
it can span multiple lines
and include single quote ' and double quotes "
IT doesn't expand the value of $lang variable

array(mixed ...$values): array

$arr1 = [10, "asd", 1.55, true];

$arr2 = ["one"=>1, "two"=>2, "three"=>3];

$arr3 = [
   [10, 20, 30],
   ["Ten", "Twenty", "Thirty"],
   ["physics"=>70, "chemistry"=>80, "maths"=>90]
];

<?php
   $arr1 = [10, 20, 30];
   $arr2 = array("one"=>1, "two"=>2, "three"=>3);

   var_dump($arr1[1]);
   var_dump($arr2["two"]);
?>

int(20)
int(2)

<?php
   $arr1 = [10, 20, 30, 40, 50];
   foreach ($arr1 as $val){
      echo "$val\n";
   }
?>

10
20
30
40
50

<?php
   $arr1 = [10, 20, 30, 40, 50];
   foreach ($arr1 as $key => $val){
      echo "arr1[$key] = $val" . "\n";
   }
?>

arr1[0] = 10
arr1[1] = 20
arr1[2] = 30
arr1[3] = 40
arr1[4] = 50

<?php
   $capitals = array(
      "Maharashtra"=>"Mumbai",
      "Telangana"=>"Hyderabad",
      "UP"=>"Lucknow",
      "Tamilnadu"=>"Chennai"
   );

   foreach ($capitals as $k=>$v) {
      echo "Capital of $k is $v" . "\n";
   }
?>

Capital of Maharashtra is Mumbai
Capital of Telangana is Hyderabad
Capital of UP is Lucknow
Capital of Tamilnadu is Chennai

class SayHello {
   function hello() {
      echo "Hello World";
   }
}

$obj=new SayHello;

<?php
   class SayHello {
      function hello() {
         echo "Hello World". PHP_EOL;
      }
   }

   $obj=new SayHello;
   var_dump(gettype($obj));
   $obj->hello();
?>

string(6) "object"
Hello World

<?php
   $obj=new stdClass;
   $obj->name="Deepak";
   $obj->age=21;
   $obj->marks=75;

   print_r($obj);
?>

stdClass Object (
   [name] => Deepak
   [age] => 21
   [marks] => 75
)

<?php
   $arr=array("name"=>"Deepak", "age"=>21, "marks"=>75);
   $obj=(object)$arr;

   print_r($obj);
?>

stdClass Object (
   [name] => Deepak
   [age] => 21
   [marks] => 75
)

<?php
   $obj=new stdClass;
   $obj->name="Deepak";
   $obj->age=21;
   $obj->marks=75;

   $arr=(array)$obj;
   print_r($arr);
?>

Array
(
   [name] => Deepak
   [age] => 21
   [marks] => 75
)

<?php
   $name="Deepak";
   $age=21;
   $percent=75.50;

   $obj1=(object)$name;
   print_r($obj1);

   $obj2=(object)$age;
   print_r($obj2);

   $obj3=(object)$percent;
   print_r($obj3);
?>

stdClass Object
(
   [scalar] => Deepak
)
stdClass Object
(
   [scalar] => 21
)
stdClass Object
(
   [scalar] => 75.5
)

time(): int

<?php
   print time();
?>

1699421347

date(string $format, ?int $timestamp = null): string

<?php
   function addition($x, $y) {
      echo "First number: " . $x;
      echo "\nSecond number: " . $y;
      echo "\nAddition: " . $x+$y;
   }

   $x="10";
   $y=20;
   addition($x, $y);
?>

First number: 10
Second number: 20
Addition: 30

<?php
   function addition($x, $y) {
      echo "First number: " . $x;
      echo "\nSecond number: " . $y;
      echo "\nAddition: " . $x+$y;
   }

   $x="Hello";
   $y=20;
   addition($x, $y);
?>

function addition(int $x, int $y) {
   echo "First number: $x Second number: $y Addition: " . $x+$y;
}

declare (strict_types=1);

Fatal error: Uncaught TypeError: addition():
Argument #1 ($x) must be of type int, string given,
called in add.php on line 12 and defined in add.php:4

Stack trace:
#0 add.php(12): addition('10', 20)
#1 {main}
   thrown in add.php on line 4

<?php
   function division(int $x, int $y): int {
      $z = $x/$y;
      return $z;
   }

   $x=20.5;
   $y=10;

   echo "First number: " . $x;
   echo "\nSecond number: " . $y;
   echo "\nDivision: " . division($x, $y);
?>

First number: 20.5
Second number: 10
Division: 2

Fatal error: Uncaught TypeError: division(): Argument #1 ($x) must be of type int, float given, called in div.php on line 12 and defined in div.php:3
Stack trace:
#0 div.php(12): division(20.5, 10)
#1 {main}
   thrown in div.php on line 3

<?php
   // declare(strict_types=1);
   function division(int $x, int $y): int {
      $z = (float)$x/$y;
      return $z;
   }

   $x=20;
   $y=10;

   echo "First number: " . $x;
   echo "\nSecond number: " . $y;
   echo "\nDivision: " . division($x, $y);
?>

First number: 20
Second number: 10PHP Fatal error:  Uncaught TypeError: division(): Return value must be of type int, float returned in /home/cg/root/14246/main.php:5
Stack trace:
#0 /home/cg/root/14246/main.php(13): division()
#1 {main}
  thrown in /home/cg/root/14246/main.php on line 5

$third = $first . $second;
$leftstring .= $rightstring;

<?php
   $a = 42;
   $b = 20;

   $c = $a + $b;
   echo "Addtion Operation Result: $c \n";

   $c = $a - $b;
   echo "Substraction Operation Result: $c \n";

   $c = $a * $b;
   echo "Multiplication Operation Result: $c \n";

   $c = $a / $b;
   echo "Division Operation Result: $c \n";

   $c = $a % $b;
   echo "Modulus Operation Result: $c \n";

   $c = $a++;
   echo "Increment Operation Result: $c \n";

   $c = $a--;
   echo "Decrement Operation Result: $c";
?>

Addtion Operation Result: 62
Substraction Operation Result: 22
Multiplication Operation Result: 840
Division Operation Result: 2.1
Modulus Operation Result: 2
Increment Operation Result: 42
Decrement Operation Result: 43

<?php
   $a = 42;
   $b = 20;

   if ($a == $b) {
      echo "TEST1 : a is equal to b \n";
   } else {
      echo "TEST1 : a is not equal to b \n";
   }

   if ($a > $b) {
      echo "TEST2 : a is greater than  b \n";
   } else {
      echo "TEST2 : a is not greater than b \n";
   }

   if ($a < $b) {
      echo "TEST3 : a is less than  b \n";
   } else {
      echo "TEST3 : a is not less than b \n";
   }

   if ($a != $b) {
      echo "TEST4 : a is not equal to b \n";
   } else {
      echo "TEST4 : a is equal to b \n";
   }

   if ($a >= $b) {
      echo "TEST5 : a is either greater than or equal to b \n";
   } else {
      echo "TEST5 : a is neither greater than nor equal to b \n";
   }
   if ($a <= $b) {
      echo "TEST6 : a is either less than or equal to b \n";
   } else {
      echo "TEST6 : a is neither less than nor equal to b";
   }
?>

TEST1 : a is not equal to b
TEST2 : a is greater than b
TEST3 : a is not less than b
TEST4 : a is not equal to b
TEST5 : a is either greater than or equal to b
TEST6 : a is neither less than nor equal to b

<?php
   $a = 42;
   $b = 0;

   if ($a && $b) {
      echo "TEST1 : Both a and b are true \n";
   } else {
      echo "TEST1 : Either a or b is false \n";
   }

   if ($a and $b) {
      echo "TEST2 : Both a and b are true \n";
   } else {
      echo "TEST2 : Either a or b is false \n";
   }

   if ($a || $b) {
      echo "TEST3 : Either a or b is true \n";
   } else {
      echo "TEST3 : Both a and b are false \n";
   }

   if ($a or $b) {
      echo "TEST4 : Either a or b is true \n";
   } else {
      echo "TEST4 : Both a and b are false \n";
   }

   $a = 10;
   $b = 20;

   if ($a) {
      echo "TEST5 : a is true \n";
   } else {
      echo "TEST5 : a is false \n";
   }

   if ($b) {
      echo "TEST6 : b is true \n";
   } else {
      echo "TEST6 : b is false \n";
   }

   if (!$a) {
      echo "TEST7 : a is true \n";
   } else {
      echo "TEST7 : a is false \n";
   }

   if (!$b) {
      echo "TEST8 : b is true \n";
   } else {
      echo "TEST8 : b is false";
   }
?>

TEST1 : Either a or b is false
TEST2 : Either a or b is false
TEST3 : Either a or b is true
TEST4 : Either a or b is true
TEST5 : a is true
TEST6 : b is true
TEST7 : a is false
TEST8 : b is false

<?php
   $a = 42;
   $b = 20;

   $c = $a + $b;
   echo "Addition Operation Result: $c \n";

   $c += $a;
   echo "Add AND Assignment Operation Result: $c \n";

   $c -= $a;
   echo "Subtract AND Assignment Operation Result: $c \n";

   $c *= $a;
   echo "Multiply AND Assignment Operation Result: $c \n";

   $c /= $a;
   echo "Division AND Assignment Operation Result: $c \n";

   $c %= $a;
   echo "Modulus AND Assignment Operation Result: $c";
?>

Addition Operation Result: 62
Add AND Assignment Operation Result: 104
Subtract AND Assignment Operation Result: 62
Multiply AND Assignment Operation Result: 2604
Division AND Assignment Operation Result: 62
Modulus AND Assignment Operation Result: 20

$third = $first . $second;

$leftstring .= $rightstring;

<?php
   $arr1=array("phy"=>70, "che"=>80, "math"=>90);
   $arr2=array("Eng"=>70, "Bio"=>80,"CompSci"=>90);
   $arr3=$arr1+$arr2;
   var_dump($arr3);
?>

array(6) {
   ["phy"]=>
   int(70)
   ["che"]=>
   int(80)
   ["math"]=>
   int(90)
   ["Eng"]=>
   int(70)
   ["Bio"]=>
   int(80)
   ["CompSci"]=>
   int(90)
}

<?php
   $arr1=array(0=>70, 2=>80, 1=>90);
   $arr2=array(70,90,80);
   var_dump ($arr1==$arr2);
   var_dump ($arr2!=$arr1);
?>

bool(true)
bool(false)

<?php
   $arr1=array(0=>70, 1=>80, 2=>90);
   $arr2=array(70,90,80);
   var_dump ($arr1===$arr2);
   $arr3=[70,80,90];
   var_dump ($arr3===$arr1);
?>

bool(false)
bool(true)

condition ? value_if_true : value_if_false

<?php
   $a = 10;
   $b = 20;

   /* If condition is true then assign a to result otheriwse b */
   $result = ($a > $b ) ? $a :$b;

   echo "TEST1 : Value of result is $result \n";

   /* If condition is true then assign a to result otheriwse b */
   $result = ($a < $b ) ? $a :$b;

   echo "TEST2 : Value of result is $result";
?>

TEST1 : Value of result is 20
TEST2 : Value of result is 10

<?php
   $arr1 = [4,5];
   $arr2 = [1,2,3, ...$arr1];

   print_r($arr2);
?>

Array
(
   [0] => 1
   [1] => 2
   [2] => 3
   [3] => 4
   [4] => 5
)

<?php
   $arr1 = [1,2,3];
   $arr2 = [4,5,6];
   $arr3 = [...$arr1, ...$arr2];

   print_r($arr3);
?>