Learning Python- Day 5

Day 5

Lists are also a popular data structure in Python.
Lists are also an ordered sequence.
Here is a list L. A list is represented with square brackets.
In many respects lists are like tuples, one key difference is they are mutable.
Lists can contain strings, floats, integers.
We can nest other lists.
We also nest tuples and other data structures; the same indexing conventions apply for nesting.

Like tuples, each element of a list can be accessed via an index.

list1=[10,20,30,40,50,60]
print("list is",list1)

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list is [10, 20, 30, 40, 50, 60]

list1=[10,20,30,40,50,60]
print("Length of list is",len(list1))

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Length of list is 6

list1=[10,20,30,40,50,60]
list1.append(70)
print(list1)

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[10, 20, 30, 40, 50, 60, 70]

To add multiple entries to the list

list1=[10,20,30,40,50,60]
list1.extend([80,90,100])
print(list1)

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[10, 20, 30, 40, 50, 60, 80, 90, 100]

list1=[10,20,30,40,50,60]
list2=list1.copy()
print(list2)

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[10, 20, 30, 40, 50, 60]

To remove last element from the list

list1=[10,20,30,40,50,60]
list2=list1.copy()
print(list2.pop())

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60

list1=[10,20,30,40,50,60]
list3=list1
print("List3 is ",list3)
print(list3.pop())
print(list3)

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List3 is  [10, 20, 30, 40, 50, 60]

60

[10, 20, 30, 40, 50]

Any change in one list will automatically make change in other list when you use = instead of copy

list1=[10,20,30,40,50,60]
list2=list1.copy()
print("List2 is",list2)
print(list2[2])

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List2 is [10, 20, 30, 40, 50, 60]

30

list1=[10,20,30,40,50,60]
list2=list1.copy()
print(list2[2:7])

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[30, 40, 50, 60]

list1=[10,20,30,40,50,60]
list2=list1.copy()
print(list2[2:7:2])

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[30, 50]

list1=[10,20,30,40,50,60]
list2=list1.copy()
print(list2[::-1])

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[60, 50, 40, 30, 20, 10]

list1=[10,20,30,40,50,60]
list2=list1.copy()
print(list2[-2])

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50

To insert a particular element at a particular index

list1=[10,20,30,40,50,60]
list2=list1.copy()
list2.insert(2,110)
print(list2)

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[10, 20, 110, 30, 40, 50, 60]

To remove particular element

list1=[10,20,30,40,50,60]
list2=list1.copy()
list2.insert(2,110)
print(list2)
list2.remove(110)
print("list2 is ",list2)

run the function CTL+shift+fn+F10

[10, 20, 110, 30, 40, 50, 60]

list2 is  [10, 20, 30, 40, 50, 60]

Removing any element from specific index

list1=[10,20,30,40,50,60]
list2=list1.copy()
print(list2.pop(3))

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40

To find index of any element

list1=[10,20,30,40,50,60]
list2=list1.copy()
print(list2.index(50))

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4

To count no of times element is repeating

list4=[1,2,3,2,1,2,1,2,3,2,1,2,3,2]
print(list4.count(2))

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7

list4=[1,2,3,2,1,2,1,2,3,2,1,2,3,2]
list4.sort()
print(list4)

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[1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3]

list4=[1,2,3,2,1,2,1,2,3,2,1,2,3,2]
list4.reverse()
print(list4)

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[2, 3, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 1]

list5=[2,7,4,3,5]
print(max(list5))

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7

print(min(list5))
print(sum(list5))

list6=[i for i in range(10)]
print(list6)

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[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

list7=[i for i in range(2,8)]
print(list7)

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[2, 3, 4, 5, 6, 7]

Converting string to list

str1="hello This is Python string"
list1=str1.split(" ")
print(list1)

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['hello', 'This', 'is', 'Python', 'string']

Converting list to string

str1="hello This is Python string"
list1=str1.split(" ")
print(list1)
str2=" ".join(list1)
print(str2)

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['hello', 'This', 'is', 'Python', 'string']

hello This is Python string

str1=input("Enter a string")
print("String is ",str1)
list1=str1.split(" ")
print("List1 is ",list1)
list1.reverse()

print("List1 is ",list1)
str2=" ".join(list1)
print(str2)

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Enter a stringthis is a sting of india

String is  this is a sting of india

List1 is  ['this', 'is', 'a', 'sting', 'of', 'india']

List1 is  ['india', 'of', 'sting', 'a', 'is', 'this']

india of sting a is this

Tuples

tuple1=(10,20,30,40,50)
print(len(tuple1))
print(tuple1[2])
print(tuple1[1:4])
print(tuple1[1:4:2])
print(tuple1[::-1])
print(tuple1.index(40))
print(tuple1.count(30))
print(min(tuple1))
print(max(tuple1))
print(sum(tuple1))

t1=(100,)
print(t1,type(t1))

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5

30

(20, 30, 40)

(20, 40)

(50, 40, 30, 20, 10)

3

1

10

50

150

(100,) <class 'tuple'>

Learning Python Day 6