Python comes with a number of built-in data types. These include primitive scalar types, like int,float,bool and None as well as collection types, like dictionaries.
Video
# int
Integer literals in python can be specified in decimal, binary, octal and hexadecimal
```python
# decimal
>>> 10
10
# binary
>>> 0b10
2
# octal
>>> 0o10
8
# hexadecimal
>>> 0x10
16
```
## Convert other types to integer
**int** constructor can be used to convert other data types like string, float to int
```python
# Convert float to integer
>>> int(2.5)
2
# Convert String to integer
>>> int("143")
143
```
# float
Python floats are implemented as IEE-754 double precision floating-point numbers with 53 bits of binary precision. This is equivalent to between 15 and 16 significant digits in decimal.
```python
>>> pi=3.1415926535
>>> pi
3.1415926535
# Scientific notation can also be used for large numbers
>>> speed_of_light=3e8
>>> speed_of_light
300000000.0
# Smaller numbers
>>> planck_constant=6.62e-34
>>> planck_constant
6.62e-34
>>> type(planck_constant)
```
## Convert other types to float
**float** constructor can be used to convert other data types like string, integer to float
```python
>>> float(4)
4.0
>>> float("4.5")
4.5
# construct not a number
>>> float("nan")
nan
# positive infinity
>>> float("inf")
inf
# Negative infinity
>>> float("-inf")
-inf
# int and float operation is promoted to float
>>> 4.3+1
5.3
```
# NoneType
Python has a special null value called None it represent the absence of a value
```python
# None value is not printed to REPL
>>> None
>>> x=None
>>> x is None
True
```
# bool
The bool type represents logical states .There are two bool values, True and False, both with initial capitals.
```python
>>> True
True
>>> False
False
>>> x = True
>>> x
True
>>>
```
## Convert other types to bool
bool constructor can be used to convert other types to boolean
- 0 is considered as False rest all are True
- empty collection is False rest all are True
- empty string is false rest all are True
```python
>>> bool(0)
False
>>> bool(0.0)
False
>>> bool(1)
True
>>> bool(1.2)
True
# Empty lists are always false
>>> bool([])
False
>>> bool([1,2])
True
# Empty string is false
>>> bool("")
False
# Note below is not empty string
>>> bool(" ")
True
# Note false is not empty string
>>> bool("False")
True
```
Bytes used by data types
Memory size of Python primitive data types depends largely on the Operating System architecture. Below size computed on my Windows 10 OS