Definitions and usage of common php functions: abs () returns the absolute value of a number.
Syntax: abs (x). The code is as follows:
$ Abs = abs (-3.2); // $ abs = 3.2
$ Abs2 = abs (5); // $ abs2 = 5
$ Abs3 = abs (-5); // $ abs3 = 5
Definition and usage: The ceil () function rounds up to the nearest integer.
Syntax ceil (x)
Parameter description
X is required. it is a number.
Note: the return value is the next integer not less than x. If x has a decimal part, the return value of ceil () is still float, because the float value range is usually larger than integer, the instance code is as follows:
Echo ceil (5); // 5
Echo"
";
Echo ceil (3.3); // 4
Echo"
";
Echo ceil (6.999); // 7
The floor () function is rounded down to the nearest integer.
Syntax: floor (x)
Parameter description
X is required. it is a number.
Note: If the return value is not greater than the next integer of x, the fractional part of x is rounded up, and the type returned by floor () is still float, because the float value range is usually larger than integer.
Echo floor (4); // 4
Echo"
";
Echo floor (3.3); // 3
Echo"
";
Echo floor (6.999); // 6
Definition and usage
The fmod () function returns the remainder of the floating point number of the division.
Syntax: fmod (x, y)
Parameter description
X is required. it is a number.
Y is required. it is a number.
Description: return the remainder of the floating point number obtained by dividing the devisor (x) by the devisor (y). The remainder (r) is defined as x = I * y + r, where I is an integer, if y is a non-zero value, the symbols of r and x are the same and the number of values is less than y. the code is as follows:
$ X = 4.7; // defines the value 1.
$ Y = 1.3; // defines the value 2.
$ R = fmod ($ x, $ y); // perform the remainder operation.
The remainder of echo $ x. "divided by". $ y. "is:". $ r; // output result
The base-10 logarithm of log10.
Syntax: log10 (x)
Parameter description
X is required. it is a number.
Description: returns the base-10 logarithm of parameter x. The code is as follows:
$ Num1 = 100;
$ Num2 = 1000;
$ Num3 = 3;
$ Result1 = log10 ($ num1 );
$ Result2 = log10 ($ num2 );
$ Result3 = log10 ($ num3 );
Echo "$ num1 base-10 logarithm $ result1 ";
Echo"
";
Echo "$ num2 base-10 logarithm $ result2 ";
Echo"
";
Echo "$ num3 base-10 logarithm $ result3 ";
Echo"
";
Log () returns the natural logarithm.
Syntax: log (x, base)
Parameter description
X is required. it is a number.
Base (optional). If this parameter is specified, logbasex is returned.
Note: if the optional parameter base is specified, log () returns logbasex; otherwise, log () returns the natural logarithm of parameter x. The instance code is as follows:
Echo log (2.7183); // returns the natural logarithm of the specified value.
Echo"
";
Echo log (2); // returns the natural logarithm of the specified value.
Echo"
";
Echo log (1); // returns the natural logarithm of a specified value.
Echo"
";
Echo log (0); // returns the natural logarithm of the specified value.
Echo"
";
Echo log (-1); // returns the natural logarithm of the specified value.
//
Echo sqrt (9); // output 3
Echo"
";
Echo sqrt (10); // 16227766...
// Open source code phpfensi.com
//
Var_dump (pow (2, 8); // 256 output
Echo"
";
Echo pow (-1, 20); // output 1
Echo"
";
Echo pow (0, 0); // output 1
Echo"
";
Echo pow (-1, 4.5); // An error is returned.