3- Variables and Data Types

What is a variable?

Variable is like a container that holds data. Very similar to how our containers in kitchen holds sugar, salt etc
Creating a variable is like creating a placeholder in memory and assigning it some value. In Python its as easy as writing:

a = 1
b = True
c = "Harry"
d = None
	```

These are four variables of different data types.

## What is a Data Type?
Data type specifies the type of value a variable holds. This is required in programming to do various operations without causing an error. \
In python, we can print the type of any operator using type function:
```python
a = 1
print(type(a))
b = "1"
print(type(b))

By default, python provides the following built-in data types:

1. Text data: string

"Hello World!!!", "Python Programming"
Why "" is required?

because if we create a variable of same name, "" will indicate that we are refering to the variable without quote.

2. Numeric data: int, float, complex

Integer:

All real numbers.

  • Example: 1-100, 10000-333333 .......

Float:

All numbers with . value.

  • Example: 10.2, 232.32323 ............

Complex:

All unreal numbers.

  • Example: 6 + 2i

3. Boolean data:

Boolean data consists of values True or False.

4. Sequenced data

list:

A list is an ordered[1] collection of data with elements separated by a comma and enclosed within square brackets.

  • Lists are mutable and can be modified after creation.

  • Example:

list1 = [8, 2.3, [-4, 5], ["apple", "banana"]]
print(list1)
  • Output:
[8, 2.3, [-4, 5], ['apple', 'banana']]
Note

As shown in example, Lists Can contain other lists

Tuple:

A tuple is an ordered[1-1] collection of data with elements separated by a comma and enclosed within parentheses.

  • Tuples are immutable and can not be modified after creation.

  • Example:

tuple1 = (("parrot", "sparrow"), ("Lion", "Tiger"))
print(tuple1)
  • Output:
(('parrot', 'sparrow'), ('Lion', 'Tiger'))

5. Mapped data:

dictionary:

A dictionary is an unordered[2] collection of data containing a key:value pair.

  • The key:value pairs are enclosed within curly brackets.

  • Example:

dict1 = {"name":"Sakshi", "age":20, "canVote":True}
print(dict1)
  • Output:
{'name': 'Sakshi', 'age': 20, 'canVote': True}

  1. Ordered data types are a type of data type that has a natural ordering or ranking. In other words, the values in an ordered data type can be put in a one-to-one correspondence with the positive integers. This means that each value can be assigned a unique position or ranking, and the values can be compared to determine their relative order. In other terms, they have an index number.↩︎↩︎

  2. Types of data that doesn't have index numbers.↩︎