Basic knowledge of PHP (ii)---2017-04-14

1. Three types of expressions for strings:

(1) Double quotation marks

(2) Single quotation mark

(3) Angle brackets

$s = <<<a

<div style= "width:500px; height:100px; Background-color:red "></div>

A must be written shelf, one line alone

2, three kinds of error prompt way

Notice: Alert Warning: Warning Error: Wrong

3, ternary operator

(1) $a = 10;

$b = 10;

echo $a = = $b? "    OK ":" NO "; -----------OK

(2) $sex = true;

echo $sex? "        Male ":" Female "; ----------Male

4. Statements

(1) Branch statements

if () {}

if () {}else{}

if () {}else if () {}

if () {if () {}}

(2) Swich statement

Switch ($a)

{

Case 1:

echo "1111";

Break

Case 2:

echo "2222";

Break

Case 3:

echo "3333";

Break

Default

echo "4444";

}

(3) Loop statement

for ($i =0; $i <10; $i + +)

{

echo "{$i}<br>";

}

(4) While statement (for dead loops, or output specific values)

$a = 0;

while ($a <10)

{

$a + +;

echo "{$a}<br>";

}*/

5. Functions

Four elements: return type function name parameter list function body

(1) Simple function

function Test ()

{

echo "Simple function";

}

Test ();

(2) function with parameters

function Test ($a)

{

echo $a;

}

Test ("Hello"); -------------Hello.

(2) function with return value

function Test ()

{

return "Test";

}

echo Test ();------------Output Testing

(4) Function of variable parameters

function Test ()

{

$arr = Func_get_args ();//Get all parameters, return array

$sum = 0;

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

{

$sum = $sum + $arr [$i];

}

return $sum;

}

echo Test (1,2,3,4,5,6,7,8,9,10);

Note: Strongly typed language functions

Public return type (void/int/string.bool) Say (int a)

{

}

6. Generate Random Numbers

echo rand (0,10); ---------- generated by seed, the default seed is the current date

7. Date and Time

(1) Echo time (),-------------the number of seconds that have been accumulated in 1970, that is, the timestamp

(2) Echo date ("Y year M D Day H:i:s");

Y year M month D Day h 24 hour hour H 12 Hour system I minute s seconds

(3) Echo strtotime ("2017-4-14 14:52:52"); Convert a string to a timestamp

Examples:

1.

$a = 10;

$b = 3;

echo $a/$b; ------3.333333

depends on what type it is (the decimal type is the decimal type; the integer is the integral type)

2.

$a = 1;

$b = $a + +; equivalent to $b= $a; $a = $a +1 first assignment after Operation

echo $b;-----1

3.

$a = 1;

$b = + + $a;   equivalent to $a= $a +1; $b = $a; Assign value after first operation

echo $b;-----2

Basic knowledge of PHP (ii)---2017-04-14