Introduction:
Welcome to Day 3 of my Python journey!
Today, I explored the fascinating world of data structures in Python, specifically lists.
These data types is crucial for storing and manipulating complex data.
LIST DATA TYPE / LIST CLASS
Basic :
\ list is a **predefined class** avaliable in python* .
* to get the manual of list class,
\>>> help ( list ) .
\ list is a collection of **similar or disimilarly** types of elements/objects.*
\ list object is python is represented by **[ ]* .
* each element avaliable in list object must be separated by coma ( , ) how to create the object of list class,
obj = list ()
print ( obj , type ( obj ))
obj = list ( [ 11, 22, 33 ] )
print ( obj , type ( obj ))
obj = [ 11, 22, 33, 44 ]
print ( obj , type ( obj ))
obj = [ 11, 1.2, 1+2j, True , None ]
print ( obj , type ( obj ) )
list store the element according to insertion order.
list is an ordered data structure. .
list supports duplicate element. .
to get the number of elements avaliable in a list object we can apply len () function .
list object is a mutable object in python because we can modify the list object.
Indexing :
index is used to perform read write update and delete a specific element in a list object. .
to provide index with list object, we have to use subscript operator.
listObj [ index] .
* index must be an integral constant .
\ valid index starts from **0 to len - 1* .
* invalid index raise IndexError .
\ list supports **-ve** index .*
* -ve index starts from -len to -1 .
\ by using index we can modify a list object in future **as per the demand** of situation.*
obj = [ 11, 22, 33, 44, 55 ]
print ( obj )
# write or update operation
obj [ 2 ] = 300
# read operation
print ( obj [ 0 ] )
print ( obj [ 1 ] )
print ( obj [ 2 ] )
print ( obj [ 3 ] )
print ( obj [ 4 ] )
print ( obj [ 0 ])
#print ( obj [ 0.0 ]) #TypeError
#print ( obj [ 10 ]) #IndexError
OPERATORS :
Basic :
all the operators available in python is not going to supported by list object .
list object supports some limited operators .
ARITHMATIC + *
+ merging
* repetation .
RELATIONAL < > <= >= == !=
relational operator returns bool type object ( True / False )
Whenever we are using comparison operators(==,!=) for List objects then the following should be considered
1. The number of elements
2. The order of elements
3. The content of elements (case sensitive)
Note: When ever we are using relatational operators(<,<=,>,>=) between List objects,only first element comparison will be performed.
ASSIGNMENT :
\= -> it create a copy of list object .
MEMBERSHIP : in not in
membership operator returns bool type object .
IDENTITY : is is not
identity operator returns bool type object
obj1 = [ 11, 22, 33 ]
obj2 = [ 44, 55 ]
obj = obj1 + obj2
print ( obj1 , obj2 , obj )
print ( obj 1 )
obj1 = [ 1, 2, 5, 4 ]
obj2 = [ 1, 2, 3, 10 ]
print ( obj1 < obj2 )
print ( 11 in [ 11, 22, 33 ] ) #True
print ( 55 in [ 11, 22, 33 ] ) #False
print ( 55 not in [ 11, 22, 33 ] ) #True
obj1 = [11, 22, 33]
obj2 = [11, 22, 33]
print (obj1 is obj2) #False
obj3 = obj1
print (obj1 is obj3 ) #True
print (obj1 is not obj2) #True
print (obj2 is obj3) #False
Ex :
obj1 = ['dog', 'cat', 'tiger']
obj2 = ['Dog', 'cat', 'tiger']
print (obj1 > obj2 )
print (obj1 != obj2 )
print (obj1 == obj2 )
x = [2,6,4]
y = [3,4,6]
z = [0, 6, 4]
print ( x > y )
print ( x != z )
x1 =['dog']
x2= ['doh']
print (x1 > x2 ) #false
print (x2 > x1 ) #True
Challenges:
Understanding list comprehension.
Handling errors.
Resources:
Official Python Documentation: Data Structures
W3Schools' Python Tutorial: Lists
Scaler's Python Course: Data Structures
Goals for Tomorrow:
Explore sets and tuple , dictionary.
Learn about handling key errors.
Conclusion:
Day 3 was a blast! Lists, tuples, and dictionaries are now under my belt.
What are your favorite data structures in Python? Share in the comments below.
Connect with me:
GitHub: https://github.com/p-archana1
LinkedIn : https://www.linkedin.com/in/archana-prusty-4aa0b827a/
Join the conversation:
Share your own learning experiences or ask questions in the comments.
Next Post:
Day 4: tuple, dictionary