Table of Contents
The append() method in python adds a single item to the existing list. It doesn’t return a new list of items but will modify the original list by adding the item to the end of the list
Every programming language has a certain number of built-in data structures. Data structures are basically structures that hold the data together so that we can use it to our advantage.
There are four built-in structures in Python:
List: It is a data structure in python which is ordered and mutable(changeable). A list allows duplicate members.
Dictionary: It is a data structure in python which is unordered, indexed and mutable. Dictionary does not allow duplicate members.
Tuple: It is a data structure in python which is ordered and unchangeable. Tuple allows duplicate members.
Set: It is a data structure in python which is unordered and unindexed. Set does not allow duplicate members.
Properties of List in Python:
- Lists are ordered: It means that lists that have the same members but different order or position are not the same.
- List elements can be accessed by index value: We can fetch the element at a specific index in the list.
- Lists are mutable: We can change or modify the elements in lists even after it has been created.
- Lists can be nested: There can be other lists inside of a list.
- Lists may contain arbitrary objects: There can be elements of several types in a single list. It means there can be float, integer and string values in a single list.
( A ) Creating a list:
a1. Create an empty list
a2. Create a list with integers only
a3. Create a list with mixed data type
We can add elements with multiple data types in list.
a4. Create a nested list
( B ) Accessing elements from a list:
b1. Accessing list elements with index value
b2. Index value must be integer
b3. We can’t access lists by string values
b4. Accessing nested list elements
b5. Accessing elements with negative index
Understanding Indexing In Python:
( C ) Slicing a list:
In slicing operation the element at stop index is not included.
c1. slicing a list with a positive index
c2. slicing a list with negative index
( D ) Changing the elements of a list:
d1. Change a single element
d2. Change multiple elements of a list
Python list methods:
( A ) append(): Add an element to the end of the list:
a1. Appending a single element
a2. Appending a list
Here we can see that the entire list is appended to the list, instead of each element.
a3. Appending a tuple
a4. Appending a set
( B ) extend() : Add all elements of a list to another list:
b1. Extending elements of a list
Here we can see that each element of the list is added to the list, instead of the entire list.
b2. Extending elements of a tuple
b3. Extending elements of set
b4. Extending using + operator
Extend() vs Append():
( C ) Insert() : insert an element at a specific index:
c1. Insert an element at 0th index
c2. Insert an element at 2nd index
c3. Insert a list
c4. Insert a tuple
c5. Insert a set
( D ) Remove() : remove an item from the list:
d1. Remove an element
d2. Removing an element with duplicate values
d3. Remove an element that doesn’t exist
( E ) pop() : It removes and returns element at the given index:
e1. Popping an element from a specified index
e2. Popping an element without index.
It deletes the last element from the list
e3. Popping an element with negative index
( F ) clear() : removes all items from a list.
f1. Using clear()
f2. Using del to clear the list
f3. Delete elements by assigning an empty list
( G ) index() : It returns the index of first matched item.
g1. Element present in the list
g2. Element not present in the list
g3. Using start index
It will start finding the element from the starting index. Default starting index is 0.
g4. Using start and end indexes
It will find the element within the given range.
( H ) count() : It returns the count of item passed:
h1. Count the number of element
h2. Count the tuple elements
( I ) sort() : sort items in ascending order:
i1. Sorting in ascending order
It changes the order of the original list.
i2. Sort in descending order
It changes the order of the original list.
i3. Using sorted
It does not change the order of the original list.
( J ) reverse() : It reverse the order of the items in the list:
j1. Reversing a list
It changes the original list.
j2. Reverse list using slicing operator
It doesn’t change the order of the original list.
j3. Using reversed() function
( K ) copy() : It returns copy of a list:
k1. Copying a list.
The main problem with this method is that, after copying the list, if we modify any of the list, both the list adept the change.
k2. Problem with previous method
Here the original list is also modified.
k3. Using copy() function
By using the copy() function we can overcome the problem mentioned above.
k4. Using slicing operation to copy a list
( L ) List membership test:
By using this method we can know whether an element is present in the list or not.
( M ) Iterating through a list:
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By Pratik Shukla
