[20-SEC SUMMARY] Given a list of list stored in variable lst. To flatten a list of lists, use the list comprehension statement [x for l in lst for x in l]. To modify all elements in a list of lists (e.g., increment them by one), use a list comprehension of list comprehensions [[x+1 for x … Read more
You can convert a list of lists to a Pandas DataFrame that provides you with powerful capabilities such as the to_csv() method. This is the easiest method and it allows you to avoid importing yet another library (I use Pandas in many Python projects anyways). Output: # file2.csv Alice,Data Scientist,122000 Bob,Engineer,77000 Ann,Manager,119000 You create a … Read more
Pandas is an open-source Python library that is powerful and flexible for data analysis. If there is something you want to do with data, the chances are it will be possible in pandas. There are a vast number of possibilities within pandas, but most users find themselves using the same methods time after time. In this … Read more
If you’re in a hurry, here’s the short answer: Use the list comprehension statement [list(x) for x in tuples] to convert each tuple in tuples to a list. This also works for a list of tuples with a varying number of elements. But there’s more to it, and studying the three main methods to achieve … Read more
If you’re in a hurry, here’s the short answer: use the list comprehension statement [tuple(x) for x in list] to convert each element in your list to a tuple. This works also for list of lists with varying number of elements. But there’s more to it and studying the two main methods to achieve the … Read more
Problem: You’re given a list of lists. Your goal is to convert it into a Pandas Dataframe. Example: Say, you want to compare salary data of different companies and job descriptions. You’ve obtained the following salary data set as a list of list: How can you convert this into a Pandas Dataframe? DataFrame() Solution: The … Read more
Short answer: Convert a list of lists—let’s call it l—to a NumPy array by using the standard np.array(l) function. This works even if the inner lists have a different number of elements. Convert List of Lists to 2D Array Problem: Given a list of lists in Python. How to convert it to a 2D NumPy … Read more
For some applications, it’s quite useful to convert a list of lists into a dictionary. Databases: List of list is table where the inner lists are the database rows and you want to assign each row to a primary key in a new dictionary. Spreadsheet: List of list is two-dimensional spreadsheet data and you want … Read more
Say, you want to convert a list of lists lst=[[1, 2], [3, 4]] into a single list [1, 2, 3, 4]. How to achieve this? There are different options: List comprehension [x for l in lst for x in l] assuming you have a list of lists lst. Unpacking [*lst[0], *lst[1]] assuming you have a … Read more
There’s an element of confusion regarding the term “lists of lists” in Python. I wrote this most comprehensive tutorial on list of lists in the world to remove all those confusions by beginners in the Python programming language. This multi-modal tutorial consists of: Source code to copy&paste in your own projects. Interactive code you can … Read more
Problem: Given a Python list with n elements. How to convert it into a tuple with the same n elements? Examples: Convert list [1, 2, 3, 4, 5] into tuple (1, 2, 3, 4, 5). Convert list [‘Alice’, ‘Bob’, ‘Ann’] into tuple (‘Alice’, ‘Bob’, ‘Ann’). Convert list [1] into tuple (1,). Note Tuple: Tuples are … Read more
Summing up a list of numbers appears everywhere in coding. Fortunately, Python provides the built-in sum() function to sum over all elements in a Python list—or any other iterable for that matter. (Official Docs) The syntax is sum(iterable, start=0): Argument Description iterable Sum over all elements in the iterable. This can be a list, a … Read more