This lecture covering the data types in python language.

1. PythonTutorials
Lecture -2-
By: Ali Sattar
To: Everyone

2. Contents:
1.What is the data type?
2.The data types in python.
3. MutableVs. Immutable objects?

3. Data type it is just determine the type of the object in your program. Python will
store that object with it’s type in the memory, also the interpreter needs to check the
status of that object for the operation later. The general from to define any variable of any
data type in python is look like below:
Variable Name = Object
A = 20
So, here A is the variable name and 20 is the object content which is assigned to the
variable, you see now how python deal with the data types.
1.What is the data type?

4. 2.The data types in python
The data types in python can be classified into five categories or classes:
2.1 Boolean.
2.2 Numeric types.
2.3 Sequences.
2.4 Sets.
2.5 Mapping.

5. 2.The data types in python
2.1 Boolean: This type has a two values either: True or False. This type can be used with
decision making statements or where we want to represent the two values.
Ex: T =True
2.2 Numeric types: This category can be classified into four data types: int, float, long
and complex.
Ex: A = 20 ; F = 2.5 ; L = 21321L ; C = 10 + 5j
► For long type now is not working in python 3.x but it was working in python 2.x and we
need to put L in the last. For complex type is just consist of a two parts: Real part and
imaginary part

6. 2.3 Sequences: This category can be classified into four data types: String, bytes, byte array, list
and tuple.
Ex:
S = “Ali Sattar” or S = str(“Hello”)  S is a string type
B1 = b1’A’  b1 is a bytes type, it is like char type in other languages.
B2 = b2’Python’  b2 is another bytes type, but it followed by sequence of letters.
BA = (“Python, Java”, “utf8”)  b is of type bytearray returns a two items only.
L = [‘String’, 24, 2.5, ‘b’]  L is of type list contains multiple items.
T = (‘One’, ‘Two’, ‘Three’)  T is of type tuple, it is similar to list but there is a difference.
2. The data types in python

7. 2.The data type in python
► For bytes data type is look like the char data type but here is expanded with not only
one byte but with a sequence of bytes like you did noticed before in the examples.
► For list it is just a sequences of items started by 0m where list object can contains many
data types for other objects ok. “List is changeable; means can be modified by insert,
update and even delete”.
► For tuple is similar to list but surround it’s items with () instead of []. “Tuple is not
changeable, so you cannot do update, insert and even delete”.
► You can use the method str() to convert any other data type to string type.
► We can use bytearray too if we want to represent a sequence of letters as list.

8. 2.4 Sets: A set is unordered collection of items inside curly braces {}. The object inside
the list is non-changeable but the set can be modified by adding or removing an items.
The set can contain items of different data types, each item inside the set is separated
comma (,) and built in using the method set(). The difference between set and list is
list items can be updated in place while set items are not.
Ex: my_Set = { 100, b’B’, “Ali Sattar”, 20.5, (1, 2, 3) }
► Here as you can see, we created a set of different items and with a different data
types.
2. The data type in python

9. 2.The data type in python
2.5 Mapping: Dictionary is the only data type here, the dictionary is unordered collection
of items (elements) where the items are surrounded by a curly braces too {} like set. Each
item is separated by comma and it has a key: value pair. Dictionary items are changeable
like list and bytearray.
Ex:
Diction1 = { 1: ‘Sunday’, 2: ‘Monday’, 3: ‘Tuesday’ }
Diction2 = { ‘A’: ‘Apple’, ‘B’: ‘Bannana’, ‘C’: ‘Chocolate’ }
Diction3 = { 12: ‘3*4’, 15: ‘3*5’}

10. 3. Mutable vs. Immutable objects
Mutable Object: It is the object in which it’s value can be changed. For example: list,
bytearray, byte and dictionary.
Immutable Object: It is the object in which it’s value cannot be changed. For example:
int, float, str, tuple and set.