May 19 Error Points Collection

1.echo, Print, Var_dump (), Print_r () Analysis:

Echo: Output variable

Print: Output variable

Var_dump (): Can output Variable type

Print_r (): Print array

2.php single and double quotes contain array speed is nothing different, single quotation marks can be output, double quotation mark inside can parse variable

The difference between 3.split,implode and explode:

split is divided in JS;explode is split in PHP

The implode () method can stitch strings into arrays

The explode () method can split the array

4. The subscript of an array can be an array or a string

5.exit () equivalent to die ()

6.global $a; You can take the value out of $ A to get inside the method.

7.

<? PHP $a = "AA"; $aa = "BB"; Echo $$a//BB

8.

<? PHP $a = ten; $b = &$a; Echo $b ; $b =15; Echo $a // 1015//a and B point to the same place, one changes to the other.

9. Stitching strings in PHP with "."

10. In PHP, there is no Add method, add with Array_push ();

One. time format output;

echo date("y-m-d h:i:s");//=> "2016-5-6 13:10:56"

12.while: First judge condition re-execution

Do While: Perform the re-judgment first

May 19 Error Points Collection