List

#Sample 

thislist = ["apple", "banana", "cherry"]

print("MyList : ",thislist)

​

thislist = ["apple", "banana", "cherry", "apple", "cherry"]

print(thislist)

MyList :  ['apple', 'banana', 'cherry']
['apple', 'banana', 'cherry', 'apple', 'cherry']

#Length of the list

thislist = ["apple", "banana", "cherry"]

print(len(thislist))

3

#Access List Items

thislist = ["apple", "banana", "cherry"]

print(thislist[1])

thislist = ["apple", "banana", "cherry", "orange", "kiwi", "melon", "mango"]

print(thislist[2:5])

thislist = ["apple", "banana", "cherry", "orange", "kiwi", "melon", "mango"]

print(thislist[:4])

thislist = ["apple", "banana", "cherry", "orange", "kiwi", "melon", "mango"]

print(thislist[2:])

banana
['cherry', 'orange', 'kiwi']
['apple', 'banana', 'cherry', 'orange']
['cherry', 'orange', 'kiwi', 'melon', 'mango']

#Check if Item Exists

thislist = ["apple", "banana", "cherry"]

if "apple" in thislist:

  print("Yes, 'apple' is in the fruits list") 

Yes, 'apple' is in the fruits list

#Change Item Value

thislist = ["apple", "banana", "cherry"]

thislist[1] = "blackcurrant"

print(thislist)

['apple', 'blackcurrant', 'cherry']

#Append Items

#To add an item to the end of the list, use the append() method

thislist = ["apple", "banana", "cherry"]

thislist.append("orange")

print(thislist)

['apple', 'banana', 'cherry', 'orange']

#Insert Items

thislist = ["apple", "banana", "cherry"]

thislist.insert(1, "orange")

print(thislist)

['apple', 'orange', 'banana', 'cherry']

#Extend List

#To append elements from another list to the current list, use the extend() method

thislist = ["apple", "banana", "cherry"]

tropical = ["mango", "pineapple", "papaya"]

thislist.extend(tropical)

print(thislist)

['apple', 'banana', 'cherry', 'mango', 'pineapple', 'papaya']

#Remove List Items

thislist = ["apple", "banana", "cherry"]

thislist.remove("banana")

print(thislist)

['apple', 'cherry']

#Remove Specified Index

#The pop() method removes the specified index

thislist = ["apple", "banana", "cherry"]

thislist.pop(1)

print(thislist)

['apple', 'cherry']

#Remove the last item

thislist = ["apple", "banana", "cherry"]

thislist.pop()

print(thislist)

['apple', 'banana']

#Delete the entire list

thislist = ["apple", "banana", "cherry"]

del thislist 

#Clear the List

#The clear() method empties the list.

#The list still remains, but it has no content.

thislist = ["apple", "banana", "cherry"]

thislist.clear()

print(thislist)

[]

#Loop Through a List

#You can loop through the list items by using a for loop

thislist = ["apple", "banana", "cherry"]

for x in thislist:

  print(x) 

apple
banana
cherry

#Loop Through the Index Numbers

#You can also loop through the list items by referring to their index number.

#Use the range() and len() functions to create a suitable iterable.

thislist = ["apple", "banana", "cherry"]

for i in range(len(thislist)):

  print(thislist[i]) 

apple
banana
cherry

#Using a While Loop

thislist = ["apple", "banana", "cherry"]

i = 0

while i < len(thislist):

  print(thislist[i])

  i = i + 1

apple
banana
cherry

#List Comprehension

fruits = ["apple", "banana", "cherry", "kiwi", "mango"]

newlist = []

​

for x in fruits:

  if "a" in x:

    newlist.append(x)

​

print(newlist) 

['apple', 'banana', 'mango']

#Sort List

thislist = ["orange", "mango", "kiwi", "pineapple", "banana"]

thislist.sort()

print(thislist)

​

thislist = [100, 50, 65, 82, 23]

thislist.sort()

print(thislist)

​

thislist = ["orange", "mango", "kiwi", "pineapple", "banana"]

thislist.sort(reverse = True)

print(thislist)

​

thislist = [100, 50, 65, 82, 23]

thislist.sort(reverse = True)

print(thislist)

['banana', 'kiwi', 'mango', 'orange', 'pineapple']
[23, 50, 65, 82, 100]
['pineapple', 'orange', 'mango', 'kiwi', 'banana']
[100, 82, 65, 50, 23]

#Customize Sort Function

def myfunc(n):

  return abs(n - 50)

​

thislist = [100, 50, 65, 82, 23]

thislist.sort(key = myfunc)

print(thislist)

[50, 65, 23, 82, 100]

#Copy List

thislist = ["apple", "banana", "cherry"]

mylist = thislist.copy()

print(mylist)

​

#Another Way

thislist = ["apple", "banana", "cherry"]

mylist = list(thislist)

print(mylist)

['apple', 'banana', 'cherry']
['apple', 'banana', 'cherry']

#List Count

fruits = ['apple', 'banana', 'cherry']

x = fruits.count("cherry")

print(x)

points = [1, 4, 2, 9, 7, 8, 9, 3, 1]

x = points.count(9)

print(x)

1
2