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# Python - Numbers

Number data types store numeric values. They are immutable data types, which means that changing the value of a number data type results in a newly allocated object.

Number objects are created when you assign a value to them. For example:

    var1 = 1
    var2 = 10

You can also delete the reference to a number object by using the del statement. The syntax of the del statement is:

    del var1[,var2[,var3[....,varN]]]]

You can delete a single object or multiple objects by using the del statement. For example:

    del var
    del var_a, var_b

Python supports four different numerical types:

- int (signed integers): often called just integers or ints, are positive or negative whole numbers with no decimal point.

- long (long integers ): or longs, are integers of unlimited size, written like integers and followed by an uppercase or lowercase L.

- float (floating point real values) : or floats, represent real numbers and are written with a decimal point dividing the integer and fractional parts. Floats may also be in scientific notation, with E or e indicating the power of 10 (2.5e2 = 2.5 x 102 = 250).

- complex (complex numbers) : are of the form a + bJ, where a and b are floats and J (or j) represents the square root of -1 (which is an imaginary number). a is the real part of the number, and b is the imaginary part. Complex numbers are not used much in Python programming.

## Examples:

Here are some examples of numbers:

int | long | float | complex
--- | --- | --- | ---
10 | 51924361L | 0.0 | 3.14j
100 | -0x19323L | 15.20 | 45.j
-786 | 0122L | -21.9 | 9.322e-36j
080 | 0xDEFABCECBDAECBFBAEl | 32.3+e18 | .876j
-0490 | 535633629843L | -90. | -.6545+0J
-0x260 | -052318172735L | -32.54e100 | 3e+26J
0x69 | -4721885298529L | 70.2-E12 | 4.53e-7j

- Python allows you to use a lowercase L with long, but it is recommended that you use only an uppercase L to avoid confusion with the number 1. Python displays long integers with an uppercase L.

- A complex number consists of an ordered pair of real floatingpoint numbers denoted by a + bj, where a is the real part and b is the imaginary part of the complex number.

# Number Type Conversion:

Python converts numbers internally in an expression containing mixed types to a common type for evaluation. But sometimes, you'll need to coerce a number explicitly from one type to another to satisfy the requirements of an operator or function parameter.

- Type int(x)to convert x to a plain integer.

- Type long(x) to convert x to a long integer.

- Type float(x) to convert x to a floating-point number.

- Type complex(x) to convert x to a complex number with real part x and imaginary part zero.

- Type complex(x, y) to convert x and y to a complex number with real part x and imaginary part y. x and y are numeric expressions

# Built-in Number Functions:

## Mathematical Functions:

Python includes following functions that perform mathematical calculations.

Function | Returns ( description )
--- | ---
abs(x) | The absolute value of x: the (positive) distance between x and zero.
ceil(x) | The ceiling of x: the smallest integer not less than x
cmp(x, y) | -1 if x < y, 0 if x == y, or 1 if x > y
exp(x) | The exponential of x: ex
fabs(x) | The absolute value of x.
floor(x) | The floor of x: the largest integer not greater than x
log(x) | The natural logarithm of x, for x> 0
log10(x) | The base-10 logarithm of x for x> 0 .
max(x1, x2,...) | The largest of its arguments: the value closest to positive infinity
min(x1, x2,...) | The smallest of its arguments: the value closest to negative infinity
modf(x) | The fractional and integer parts of x in a two-item tuple. Both parts have the same sign as x. The integer part is returned as a float.
pow(x, y) | The value of x**y.
round(x [,n]) | x rounded to n digits from the decimal point. Python rounds away from zero as a tie-breaker: round(0.5) is 1.0 and round(-0.5) is -1.0.
sqrt(x) | The square root of x for x > 0

## Random Number Functions:

Random numbers are used for games, simulations, testing, security, and privacy applications. Python includes following functions that are commonly used.

Function | Returns ( description )
--- | ---
choice(seq) | A random item from a list, tuple, or string.
randrange ([start,] stop [,step]) | A randomly selected element from range(start, stop, step)
random() | A random float r, such that 0 is less than or equal to r and r is less than 1
seed([x]) | Sets the integer starting value used in generating random numbers. Call this function before calling any other random module function. Returns None.
shuffle(lst) | Randomizes the items of a list in place. Returns None.
uniform(x, y) | A random float r, such that x is less than or equal to r and r is less than y

## Trigonometric Functions:

Python includes following functions that perform trigonometric calculations.

Function | Description
--- | ---
acos(x) | Return the arc cosine of x, in radians.
asin(x) | Return the arc sine of x, in radians.
atan(x) | Return the arc tangent of x, in radians.
atan2(y, x) | Return atan(y / x), in radians.
cos(x) | Return the cosine of x radians.
hypot(x, y) | Return the Euclidean norm, sqrt(x*x + y*y).
sin(x) | Return the sine of x radians.
tan(x) | Return the tangent of x radians.
degrees(x) | Converts angle x from radians to degrees.
radians(x) | Converts angle x from degrees to radians.

# Mathematical Constants:

The module also defines two mathematical constants:

Constant | Description
--- | ---
pi | The mathematical constant pi.
e | The mathematical constant e.

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