Write well, work well - PHP basics (2), work well - PHP basics_PHP tutorial

Write well, do it well - PHP basics (2), do it well - PHP basics

　hi

I haven’t written for a long time. When I wrote yesterday, I feel like some people still read it, at least one or two comments~~ Good job!

There are only 4 things that you need to stick to every day: write this, learn a little French, read for a while, and exercise. There are benefits to being single.

1. PHP

1. PHP Basics (2)

1.3 Data Type

8 types - 4 types of scalars: boolean, integer, float/double, string; 2 types of composite: array, object; 2 special types: resource, NULL None;

It is recommended to remember English. In the process of learning, variables are usually named this way.

php is a weakly typed language , that is, there is no need to declare the type of variables in advance.

View the type of variable: gettype();

Judgment type: is_*(), where * is the abbreviation of various data types.

1.3.1 Boolean

True or false is not case-sensitive. It is customary (for me) to write all lowercase letters.

Generally there is no need to force conversion to Boolean value, the system will automatically judge; (see the example below)

These are considered false: false; 0; 0.0; empty string and string "0"; empty array; NULL; SimpleXML object generated from empty tag (I don't understand it very well yet, mainly XML is not involved yet);

Correspondingly, everything else is considered true - Note that -1 is also true;

$boola=true;
$boolb=false;
$boolc=null;
$boold=-1;
$boole="sdkljf";

echo gettype($boola)."

---

";

function isbool($bool){
if(is_bool($bool)){
echo "You are damn right.It is boolean."."
}else{
echo "Sorry, it is not this type. Please try again."."
";
}
}

isbool($boola);
isbool($boolc);
isbool($boold);
isbool($boole);

function booluse($bool){
if($bool){
echo "It is equal to TRUE."."
";
}else{
echo "It is equal to FALSE."."
";
}
}

booluse($boola);
booluse($boolc);
booluse($boold);

In the above example, please note that if you directly determine whether it is boolean, the general data type will not be forced to convert. Only when used in if and other judgments, it will be automatically and forcibly converted to boolean for use.

1.3.2 Int

Integer type.

I was wrong. . . Halfway through writing, my boss called me to work overtime, and I promise to finish the first part of the series tomorrow (I mean I want to watch Chinatown tonight...).

Good night, I went to read a book

http://www.bkjia.com/PHPjc/1087780.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/1087780.htmlTechArticleWrite well, do well - PHP basics (2), do well - PHP basics hi I haven’t written for a long time, yesterday As soon as I wrote it, I felt like someone would read it, at least one or two comments~~ Good job! Need to be strong every day...