java.lang.integer Usage analysis of integer type in PHP

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: integer overflows time, 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.
Convert to integer:
boolean 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, Then 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.
array type conversion 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 object type value to integer will produce something like Notice information of Object of class stdClass could not be converted to int. The result of the conversion is 1;
string converted 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, the string will Convert to integer.

Copy the 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 resources type When the value is converted to integer, the id corresponding to the resource will be converted to integer:
1. Converting null to integer is always 0.
Converting undefined variables to integer:
1. Converting undefined variables to integer will generate a notice message and convert it to 0.

The above introduces the analysis of the use of integer type in java.lang.integer PHP, including the content of java.lang.integer. I hope it will be helpful to friends who are interested in PHP tutorials.