Accessing List Elements
Similar to strings, items are stored into a list according to their index. Any item can be accessed using its index value.
- The list index can be either positive or negative integer.
- The positive index starts from 0 and negative starts from -1.
#Each element can be accessed by its index value >>>list=[11,22,33,44,55,66,77,88,99] >>>list1 11 #Negative values can also be used here >>>list1[-2] # Here -2 will be treated as length of list-2 88 >>>list1[-5] 55
Traversing a list
Traversing means to travel across a list or to access all of its elements(items).
There are two ways to traverse a list in Python:
Using ‘in’ operator
- ‘in’ operator is used to check whether the element is present in the list or not.
- If you want to check the character is present in the list or not you can use this operator. It is useful in that case.
- It can be used in for loop as iterator on the list. As shown in the below example.
>>>list1=['F','R','E','S','H','L','Y','B','U','I','L','T'] >>>for i in list1: >>> print(i) #Here i is the iterator F R E S H L Y B U I L T
Using range() function
- range() function in python is used for transversing of the list.
- The numerical value or range value is passed inside the function for providing transversing limit.
- It can also be used for traversing the list by leaving the element inside the list in a fixed manner.
- For example, is we have to traverse over ‘ram’ we can also transverse over ‘ram’ by iterating over ‘r’ and ‘m’ and leaving a behind i.e range(3,1) # 3 equal to length of the word and 1 signify that we have to leave single character after taking out one character while traversing over the list.
>>>list1=['F','R','E','S','H','L','Y','B','U','I','L','T'] >>>n=len(list1) #here n is length of the list >>>for i in range(n): >>> print(list1[i]) #Here i is the iterator F R E S H L Y B U I L T