Lists in Python
As we are going through various data type available in the python. In this article, we are going to explore more about the most used data structure list/sequence. List in python is one of the most basic data structure. Each element of the list is assigned a number, which is called index of the element. The first element’s index will be zero, then all subsequent element have index in incremental order. List are immutable in Python, which means python will not create a new list if we modify an element of the list. List is created by storing a sequence of different types of values separated by commas.
Python list is enclosed between
Defining Lists:
List syntax:
<list_name>=[value1,value2,…,valuen];
Example:
my_list = [1,2,3,4,7] my_list = [1,2,”String1”,”String2”]
Similar to string indices, list indices start at 0, and lists can be sliced, concatenated and so on.
Accessing Values in Lists:
To access values in lists, use the square brackets for slicing along with the index or indices to obtain value available at that index as shown in below example:
my_list = [1, 2, 3, 4, 7]
my_mix_list = [1, 2,"String1", "String2"]
print("my_list[2]: "+ str(my_list[2]))
print(my_mix_list[2:])This code will produce below output:
Output: my_list[2]: 3
[‘String1’, ‘String2’]
Append or update lists:
Let's assume we have a list called my_list and it is defined as below. Now we will see various operation over it.
my_list = [1, 2, 3, 4, 7]
Add New element
To add
my_list.append(“Append This!!”) print(my_list)
Output:
[1, 2, 3, 4, 7, “Append This!!”]
To update Element in the list we can directly use list index where we want to update the value as below:
my_list[4] = 5 print(my_list)
Output:
[1, 2, 3, 4, 5, “Append This!!”]
To delete the element at any index we can use
del my_list[5] print(my_list)
Output:
[1, 2, 3, 4, 7]
There are many built-in functio
Methods with Description |
list.count(obj)
Returns count of occurrence of the object in |
list.sort([sortme])
Sorts objects of |
list.extend(let)
Appends the contents of |
list.index(obj) Return the index of the first occurrence of the object |
list.append(obj) Appends object obj to list |
list.pop(obj=list[-1]) Removes and returns last object or obj from list |
list.insert(index, obj)
Inserts object obj into |
list.remove(obj) Removes object obj from list |
list.reverse() This will reverse the objects in the list |
Function with Description |
Compares elements of both lists. |
min(list) Return the minimum from the list |
len(list)
Returns to |
list(seq) Converts given tuple to list |
max(list) Returns the maximum from the list |
That's it for the list. If you play little bit more with the methods above, you will get to understand what each of the methods are doing and where which method/function can be used.
That's all for this topic. If you guys have any suggestions or queries, feel free to drop a comment. We would be happy to add that in our post. You can also contribute your articles by creating contributor account here.
Happy Learning 🙂
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Tags: python
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