Conversion and detection of PHP data types

This article mainly introduces the PHP data type conversion and detection, has a certain reference value, now share to everyone, the need for friends can refer to

1. Conversion of data types

Although PHP is a weakly typed language, it is also possible to convert data in the same way as the C language, simply by enclosing the variable with the type name in parentheses.

1. Convert to Boolean type: (Boolean)

   Str

2. Convert to Character type: (String)

   Flo

3. Convert to Integer type: (integer)

   Str

4. Convert to Floating point type: (float) $str

5. Convert an array: such as (arrays) $str

6. Convert to object: (Obiect) $str

Note: In the process of type conversion, you should be aware of the following: when converted to Boolean, NULL, 0, and unassigned variables or arrays are converted to false, and the others are true; When converting to an integer, the Boolean conversion to 0,true is converted to 1, and the decimal portion of the floating-point type is removed, and the character type is truncated to a non-number-bit if it starts with a number, otherwise the output is 0.

Another type conversion can also be set by the Settype function.
BOOL Settype (mixed var,string type)
Note: The parameter var is the specified variable; The parameter type is the specified data type. The parameter type has 7 optional values, Boolean, float,. Integer, array, null, object, and string. If the conversion succeeds, the Settype () function returns True, otherwise false is returned.
When a string is converted to an integer or float, if the string starts with a number, it first converts the number part to an integer, and then goes back to the string; If the number contains a decimal point, it is taken to the previous digit in the decimal point.

2, the data type detection

1. is bool checks if the variable is a Boolean type: is bool (true), Is_bool (false)

2. is_string Check if the variable is a string type: is_string (' string ') is_string (1234)

3. is float/is double checks if the variable is a floating-point type: Is_float (3.1415), Is_float (3 1415)

4. Is_integer/is_int Check if the variable is an integer: such as Is_integer (34), Is_integer (' 34 ')

5. Is_null checks if the variable is null: Is_null (NULL)

6. Is_array Check if the variable is of the array type: I_sarray ($arr)

7. Is_object Check if the variable is an object type: Is_object ($obj)

8. Is_numeric checks whether a variable is a number or a string consisting of a number: such as Is_numeric (' 5 '), Is_numeric (' Aabb ')