- List<\/li>
- Tuples<\/li>
- Dictionaries<\/li>
- Sets<\/li><\/ul>\n\n\n\n
We will review each in more detail and also try to see what could be the practical applications for each of these data structures.<\/p>\n\n\n\n
Before we look at the different data structures, we will look at the concept of Strings.<\/p>\n\n\n\n
Strings:<\/h4>\n\n\n\n
\n- A String is an immutable data type (means it cannot be changed)<\/li>
- It is a sequence of Unicode characters wrapped inside single, double, or triple quotes.<\/li>
- Examples of strings are ‘Today is Saturday’, “Today is a Holiday”, “” Tomorrow is Sunday”””<\/li>
- Use print command to print a string
- e.g. string1= ‘ Today is Saturday’ <\/li>
- print(string1)<\/li>
- Output- ‘ Today is Saturday’<\/li><\/ul><\/li>
- Use length function to determine the length of the string as shown in below screenshot<\/li><\/ul>\n\n\n\n
![\"\"](\"https:\/\/thenontechieguy.com\/wp-content\/uploads\/2021\/08\/Python-len-function-1024x576.png\")
<\/figure>\n\n\n\n- Strings support indexing- which means you can retrieve a certain character from the string<\/li>
- Use below syntax:
- IF Day=’Saturday’, then Day[1]= a- note that index starts at 0 and 1st character of this string can be retrieved as Day[0]= S<\/li>
- Note: use print statement to print the results<\/li><\/ul><\/li><\/ul>\n\n\n\n
![\"\"](\"https:\/\/thenontechieguy.com\/wp-content\/uploads\/2021\/08\/image-2-1024x576.png\")
<\/figure>\n\n\n\n- Note that Python supports negative indexing. To retrieve the last character of a string, use -1<\/li>
- Using the above example, Day[-1]=y and Day[-2]=a<\/li><\/ul>\n\n\n\n
<\/p>\n<\/div><\/div>\n\n\n\n
In this post, we will look at the concept of ‘Lists’ in Python in more details<\/p>\n\n\n\n
Lists in Python- A Basic Understanding: <\/h4>\n\n\n\n
- A list is a collection of comma separated values written within square brackets<\/li>
- Example of a list in python:
- even_numbers_greater_than_zero=[2,4,6,8,10]<\/li><\/ul><\/li>
- A few of the important characteristics of Lists are as below:
- Lists may contain items of same or different types (e.g. int, float, string etc.). <\/li>
- homogeneous_list= [2,7,9,11,13]<\/li><\/ul>
- heterogenous_list=[“yes”, 1, “True”]- note that the list has different types- integers and strings in this case<\/li>
- Lists can be indexed
- even_numbers_greater_than_zero=[2,4,6,8,10]<\/li>
- even_numbers_greater_than_zero[2]=6 #indexing returns the required item<\/li><\/ul><\/li>
- Lists can be sliced
- even_numbers_greater_than_zero[-3:]= [6,8,10] #slicing returns last 3 items of the list to create a new list<\/li><\/ul><\/li>
- Lists can support concatenation
- even_numbers_greater_than_zero=[2,4,6,8,10]<\/li>
- even_numbers_greater_than_zero_additional= [12,14,16,18]<\/li>
- print (even_numbers_greater_than_zero+even_numbers_greater_than_zero_additional)=[2,4,6,8,10,12,14,16,18]- creates a new list which contains a new list with items from both of the above lists<\/li><\/ul><\/li>
- Lists are mutable- which means it is possible to change its content
- even_numbers_greater_than_zero=[2,4,6,8,10]<\/li>
- even_numbers_greater_than_zero[2]= 7<\/li>
- even_numbers_greater_than_zero=[2,4,7,8,10] #the 3rd element in this list is modified based on the above statement<\/li><\/ul><\/li>
- Lists support len function
- While using the len function with lists, it lists down the number of items in the list<\/li>
- len(even_numbers_greater_than_zero)= 5<\/li><\/ul><\/li>
- It is possible to create nested lists
- even_numbers_greater_than_zero=[2,4,6,8,10]<\/li>
- odd_numbers_greater_than_zero=[1,3,5,7,9]<\/li>
- numbers= [even_numbers_greater_than_zero, odd_numbers_greater_than_zero]<\/li>
- print(numbers)=[[2,4,6,8,10], [1,3,5,7,9]] #Python created a list of nested lists<\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n
Lists in Python- When to use?<\/h4>\n\n\n\n
- Use a list when you want to store different kinds of data type that may need to be changed in future<\/li>
- Use a list when you want to manipulate the data using slicing, concatenating, updating, deleting items in the list.<\/li><\/ul>\n\n\n\n
The above is my basic understanding of Lists as I teach myself the concept of ‘Lists’ as a part of Python data structures.<\/p>\n\n\n\n
In subsequent posts, I will try to cover my understanding of other data structures in Python.<\/p>\n\n\n\n
References:<\/h3>\n\n\n\n
I am using the official Python documentation for learning Python<\/p>\n\n\n\n
Below is the link for reference (I am working on Python 3.9.6 version)<\/p>\n\n\n\n