Access List Items In Python
We are studying Python access list with examples in this chapter in the hope that it will fulfil the needs in learning.
Python Access List Item
Items in a list are indexed, so you can navigate them by using their index numbers:
On the list, print the fourth item:
Example
Note: Index 0 is assigned to the first item.
Negative Indexing:
The negative indexing method starts at the end and goes backward.
The last item is numbered -1,
The -2 indicates the second last item, etc.
On the list, print the last item:
Example
Negative Index Range
In Python access lists, specify negative indices if you would like to start searching from the end:
Using this example, we return all items from “Spain” (-7) to, but exclude “USA” (-1):
Example
Index Range:
Python access lists allow you to set a range of indexes by assigning a starting point and an ending point.
If you define a range, the returned list will contain all the items in that range.
The fourth, fifth, and sixth items should be returned as follows:
Example
Note: It should be noted that the search will start at index 2 (included) and end at index 5 (not included).
In the absence of a start value, the range will start at the first item in the list:
In this example, items are returned from the beginning to, but not including, “Maldives”:
Example
If the range doesn’t contain a value at the end, it will go on to the end of the list:
In this example, we return the items from “Brazil” to the end:
Example
Check if Item Exists
We can use the in keyword to check if an item exists in Python access lists:
Verify that “Germany” appears in the list:
Example
Python Access List Uses
Following are uses of list access attributes:
- Accessing elements in a list allows you to retrieve specific values based on their index position. This can be useful when you need to retrieve and work with individual elements of a list.
- Accessing a list allows you to iterate over its elements using loops, such as the
forloop. This allows you to perform operations on each element or extract information from the list. - You can check if an element is present in a list by accessing the list and using the
inoperator. This allows you to quickly determine whether a certain value exists in the list. - List slicing enables you to extract a subset of elements from a list based on a range of indices. This allows you to work with specific portions of a list, such as extracting the first few elements or excluding certain elements.
- Accessing a list allows you to modify individual elements by assigning a new value to the corresponding index. This is useful when you need to update or change specific elements within a list.
- Accessing a list can be combined with other operations, such as conditionals or functions, to perform more complex tasks. For example, you can access specific elements based on certain conditions or use the values to perform calculations or transformations.
