Be a part of our community of 1M+ users who develop and demonstrate their skills on CodeSignal
4 courses
66 practices
4 hours
Learn to organize and process groups of values with Python’s core collections. Work with strings, lists, and dictionaries; access, add, update, and remove data; iterate through collections; and choose the right structure for practical data-processing problems.
Text shows up everywhere in real programs: names, messages, files, and user input. You will pinpoint characters by position, carve out substrings with slicing, clean and reshape text using built-in methods, and search, split, and join strings to pull out exactly the pieces you need.
Lists let you hold many values together and treat them as a single collection. Beginning with creating lists and accessing elements by position, you will extract sublists with slicing, add and remove items, change and sort contents, check for particular values, and combine lists. These skills prepare you to process collections with loops in the next path.
When data carries labels instead of positions, dictionaries map keys to values for fast, readable lookups. You will create and query them, add and update entries, iterate over keys and values, and nest lists and dictionaries to model the structured records real applications depend on.
Bring strings, lists, and dictionaries together to tackle problems practitioners face daily. You will count and group values, filter and transform collections with comprehensions, parse raw text into structured records, and aggregate everything into clear summaries and reports.
Hear what our customers have to say about CodeSignal Learn
I'm impressed by the quality and can't stop recommending it. It's also a lot of fun!
Francisco Aguilar Meléndez
Data Scientist
+11
I love that it's personalized. When I'm stuck, I don't have to hope my Google searches come out successful. The AI mentor Cosmo knows exactly what I need.
Faith Yim
Software Engineer
+14
It's an amazing product and exceeded my expectations, helping me prepare for my job interviews. Hands-on learning requires you to actually know what you are doing.
Alex Bush
Full Stack Engineer
+9
I'm really impressed by the AI tutor Cosmo's feedback about my code. It's honestly kind of insane to me that it's so targeted and specific.
Abbey Helterbran
Tech consultant
+8
I tried Leetcode but it was too disorganized. CodeSignal covers all the topics I'm interested in and is way more structured.
Jonathan Miller
Senior Machine Learning Engineer
+12
I'm impressed by the quality and can't stop recommending it. It's also a lot of fun!
