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Access List Items
Python Tutorial
This Python tutorial has been written for the beginners to help them understand the basic to advanced concepts of Python Programming Language. After completing this tutorial, you will find yourself at a great level of expertise in Python, from where you can take yourself to the next levels to become a world class Software Engineer.
Access List Items
In Python, a list is a sequence. Each object in the list is accessible with its index. The index starts from 0. Index or the last item in the list is "length-1". To access the values in a list, use the square brackets for slicing along with the index or indices to obtain value available at that index.
The slice operator fetches one or more items from the list. Put index on square brackets to retrieve item at its position.
obj = list1[i]
Example 1
Take a look at the following example
list1 = ["Rohan", "Physics", 21, 69.75]list2 = [1, 2, 3, 4, 5]
print ("Item at 0th index in list1: ", list1[0])print ("Item at index 2 in list2: ", list2[2])
It will produce the following output
Item at 0th index in list1: RohanItem at index 2 in list2: 3
Python allows negative index to be used with any sequence type. The "-1" index refers to the last item in the list.
Example 2
Let's take another example
list1 = ["a", "b", "c", "d"]list2 = [25.50, True, -55, 1+2j]
print ("Item at 0th index in list1: ", list1[-1])print ("Item at index 2 in list2: ", list2[-3])
It will produce the following output
Item at 0th index in list1: dItem at index 2 in list2: True
The slice operator extracts a sublist from the original list.
Sublist = list1[i:j]
Parameters
- i − index of the first item in the sublist
- j − index of the item next to the last in the sublist
This will return a slice from ith to (j-1)th items from the list1.
Example 3
While slicing, both operands "i" and "j" are optional. If not used, "i" is 0 and "j" is the last item in the list. Negative index can be used in slicing. Take a look at the following example −
list1 = ["a", "b", "c", "d"]list2 = [25.50, True, -55, 1+2j]
print ("Items from index 1 to 2 in list1: ", list1[1:3])print ("Items from index 0 to 1 in list2: ", list2[0:2])
It will produce the following output
Items from index 1 to 2 in list1: ['b', 'c']Items from index 0 to 1 in list2: [25.5, True]
Example 4
list1 = ["a", "b", "c", "d"]list2 = [25.50, True, -55, 1+2j]list4 = ["Rohan", "Physics", 21, 69.75]list3 = [1, 2, 3, 4, 5]
print ("Items from index 1 to last in list1: ", list1[1:])print ("Items from index 0 to 1 in list2: ", list2[:2])print ("Items from index 2 to last in list3", list3[2:-1])print ("Items from index 0 to index last in list4", list4[:])
It will produce the following output
Items from index 1 to last in list1: ['b', 'c', 'd']Items from index 0 to 1 in list2: [25.5, True]Items from index 2 to last in list3 [3, 4]Items from index 0 to index last in list4 ['Rohan', 'Physics', 21, 69.75]
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