By: Archana Shukla and Rajesh Shukla
Lists Contd…
Loop through list
l1=[10,20,30,40,50]
for i in l1:
print (i)
check if the item is in the list
l1=[10,20,30,40,50]
if 10 in l1:
print(“yes it is in the list”)
Built-in list functions
| Function | Description | Example |
| len(list) | Returns total no of items in the list | lst=[10,20,30,40] print(len(lst)) 4 |
| max(list) | Returns the item with largest value in the list | |
| min(list) | Returns the item with smallest value in the list | |
| list(seq) | Converts a tuple or string into a list | |
| sum(list) | Adds all the numeric values present in the list |
List Methods
| Method | Description | Example |
| append() | Adds an element at the end of the list | >>>flower=[‘rose’,’lily’,’lotus’] >>>flower.append(‘jasmine’) >>>flower [‘rose’, ‘lily’, ‘lotus’, ‘jasmine’] |
| index() | Returns the index of the first element with the specified value | >>>flower.index(‘lily’) 1 |
| insert() | Adds an element at the specified position | >>>flower.insert(2,’sunflower’) >>>flower [‘rose’, ‘lily’, ‘sunflower’, ‘lotus’, ‘jasmine’] |
| sort() | Sorts the list | >>>flower.sort() >>>flower [‘jasmine’, ‘lily’, ‘lotus’, ‘rose’, ‘sunflower’] |
| remove() | Removes the item with the specified value | >>>flower.remove(‘lotus’) >>>flower [‘jasmine’, ‘lily’, ‘rose’, ‘sunflower’] |
| reverse() | Reverses the order of the list | >>>flower.reverse() >>>flower [‘sunflower’, ‘rose’, ‘lily’, ‘jasmine’] |
| pop() | Removes the element at the specified position or the last item if the index is not specified | >>>flower.pop(1) ‘rose’ >>>flower [‘sunflower’, ‘lily’, ‘jasmine’] |
| clear() | Empties the list or Removes all the elements from the list | |
| count() | Returns the number of elements with the specified value | >>>l1=[1,2,3,1,4,5,1,6,1,8] >>>l1.count(1) 4 |
| extend() | Add the elements of a list (or any iterable), to the end of the current list | >>>lst=[10,20,30,40] >>>lst1=[50,60,70,80] >>>lst.extend(lst1) >>>lst [10, 20, 30, 40, 50, 60, 70, 80] |
| copy() | Returns a copy of the list | >>>l1=[‘a’,’b’,’c’,’d’,’e’] >>>l2=l1.copy() >>>l2 [‘a’, ‘b’, ‘c’, ‘d’, ‘e’] |
| del keyword | Removes the specified index Or removes the complete list if the index is not specified | >>>l1=[‘a’,’b’,’c’,’d’,’e’] >>>del l1[1] >>>l1 [‘a’, ‘c’, ‘d’, ‘e’] |
Joining two lists
We can use + operator to combine two lists. This is also called concatenation
n=[1,2,3,4,5]
n1=[6,7,8,9,10]
print("list n")
print(n)
print("list n1")
print(n1)
print("n+n1")
print(n+n1)
#[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print(n+[10,20,30])
Output
list n
[1, 2, 3, 4, 5]
list n1
[6, 7, 8, 9, 10]
n+n1
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
[1, 2, 3, 4, 5, 10, 20, 30]
Nested list
list within a list
n=["computer",[10,20,30,40]] print(n[0][0]) print(n[0][1]) print(n[0][2]) print(n[0][3]) print(n[0][4]) print(n[1][0]) print(n[1][1]) print(n[1][2]) print(n[1][3])
Output
c
o
m
p
u
10
20
30
40
