Usage analysis of integer type in PHP_PHP tutorial

Integer can be expressed in decimal, octal, or hexadecimal.
When expressed in octal, the number needs to start with 0 (zero);
When expressed in hexadecimal, the number needs to start with 0x (zero x) or 0X (zero capital X);

integer overflow: When integer overflows, it will be automatically converted to float type. Similarly, if the operation result of integer type exceeds the boundary of integer type, it will be automatically converted to float type.
One thing to note is that the integer type does not have a "/" (division) operation. If you need to obtain an integer, you can use functions such as round, or directly use (int) or (integer) to force type conversion to integer. .

is converted to integer:
boolean is converted to integer:
1, true is always converted to 1;
2, false is always converted to 0;
float is converted to integer :
1. If the float type value does not exceed the boundary value of integer, the decimal part will be cut off directly during conversion.
2. If the float type value exceeds the boundary value of integer, the conversion result is undefined, but it is almost certainly not the expected result.
Convert array type to integer:
1. Empty array is always converted to 0;
2. Non-empty array is always converted to 1;
Object is converted to integer:
1. Converting a value of type object to integer will generate a Notice message similar to Object of class stdClass could not be converted to int. The conversion result is 1;
Convert string to integer:
1. If the string starts with a number and does not contain the characters '.', 'e', ​​'E', and the value of the number is within the range of integer Within, string will be converted to integer.

Copy code The code is as follows:

$resource = fopen('d:/tmp/test.txt', 'rb ');
var_dump($resource, (int)$resource);

2. If string is an empty string or does not start with a number, string can be converted to integer 0;
3. In other cases, string will be converted to float type;
resources converted to integer:
1. Convert the value of resources type to integer, and the id corresponding to the resource will be
for example:
Results of

Copy code The code is as follows:

resource(3) of type (stream) int(3 )

null is converted to integer:
1. null is converted to integer and is always 0
Undefined variables are converted to integer:
1. Undefined variables are converted to integer A notice message will be generated and converted to 0

http://www.bkjia.com/PHPjc/322190.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/322190.htmlTechArticleinteger can be expressed in decimal, octal or hexadecimal. When expressed in octal, the number needs to start with 0 (zero); when expressed in hexadecimal, the number needs to start with 0x (zero x) or...