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## 1. Python integer values

In Python, an `int` or integer is:

• a whole number without decimal
• positive, negative or zero
• of unlimited length
• may contain underscores to improve readability
 `x ``=` `10``y ``=` `12345678987654321``z ``=` `12_34_56` `print``(x)            ``# 10``print``(y)            ``# 12345678987654321``print``(z)            ``# 123456`

## 2. Integers can be octal and hex

In python, we can represent the integers in the octal or hexadecimal representation also.

• Octal and hexadecimal numbers can be negative, but cannot be written in the exponential form.
• Octals are prefixed with `'0o'` (zero followed by the letter “o”) and contains digits from 0 to 7.
• Hexadecimals prefixed with `'0x'` (zero followed by the letter “x” – uppercase or lowercase) and contains digits from 0 to 9 or letters from A to F (uppercase or lowercase).
 `octalInt ``=` `0o22``hexInt ``=` `0xAA` `print``(octalInt)     ``# 18``print``(hexInt)       ``# 170`

## 3. Arithmetic operations

#### 3.1. Addition, subtraction, multiplication and devision

These operations are pretty much similar to other languages.

The standard operation of division, which is performed by the `/` operator, generally returns a floating-point result. Use the floor division operator `//` to remove the digits after the decimal point.

• `x / y` : returns quotient of x and y
• `x // y` : returns (floored) quotient of x and y
• `x % y` : remainder of x / y
• `divmod(x, y)` : the pair (x // y, x % y)
 `x ``=` `22``y ``=` `5` `print` `(x ``+` `y)           ``# Prints 27``print` `(x ``-` `y)           ``# Prints 17``print` `(x ``*` `y)           ``# Prints 110` `print` `(x ``/` `y)           ``# Prints 4.4``print` `(x ``/``/` `y)          ``# Prints 4``print` `(x ``%` `y)           ``# Prints 2``print` `( ``divmod``(x, y) )  ``# Prints (4, 2)`

#### 3.2. Increment and decrement

• Increment `(+=x)` adds `x` to the operand.
• Decrement `(-=x)` subtracts `x` to the operand.
 `x ``=` `10``y ``=` `10` `x ``+``=` `1``print` `(x)   ``# Prints 11` `x ``+``=` `5``print` `(x)   ``# Prints 16` `y ``-``=` `1``print` `(y)   ``# Prints 9` `y ``-``=` `5``print` `(y)   ``# Prints 4`

#### 3.3. Exponent

Exponential calculation is possible using `**` operator.

 `x ``=` `10``y ``=` `2` `print` `(x ``*``*` `y)  ``# Prints 100`

## 4. isinstance to check type

If you want to verify if an integer belongs to the class int you can use `isinstance`.

 `x ``=` `10` `print``( ``isinstance``(x, ``int``) ) ``# Prints True`

## 5. Convert Integer to String

Use string constructor `str()`.

 `x ``=` `10` `valueOfX ``=` `str``( x )     ``# '10'`

## 6. Convert String to Integer

Use integer constructor `int()`.

 `valueOfX ``=` `'10'` `x ``=` `int``( valueOfX )     ``# 10`