Explanation of how nested list comprehension works?

by

Ah, the incomprehensible “nested” comprehensions. Loops unroll in the same order as in the comprehension.

[leaf for branch in tree for leaf in branch]

It helps to think of it like this.

for branch in tree:
    for leaf in branch:
        yield leaf

The PEP202 asserts this syntax with “the last index varying fastest” is “the Right One”, notably without an explanation of why.

More Related Contents:

  1. I don’t know how to display step 3 for this assignment
  2. Extract first item of each sublist
  3. How to avoid “RuntimeError: dictionary changed size during iteration” error?
  4. How to find all positions of the maximum value in a list?
  5. In Python, what is the difference between “.append()” and “+= []”?
  6. Pandas DataFrame stored list as string: How to convert back to list
  7. a mutable type inside an immutable container
  8. How can I convert a dictionary into a list of tuples?
  9. Pythonic way of checking if a condition holds for any element of a list
  10. Different ways of clearing lists
  11. Merge multiple column values into one column in python pandas
  12. How to get item’s position in a list?
  13. How to find the min/max value of a common key in a list of dicts?
  14. How does the max() function work on list of strings in python?
  15. Complexity of list.index(x) in Python
  16. How to transform string of space-separated key,value pairs of unique words into a dict
  17. Nested list comprehensions
  18. How to convert list of numpy arrays into single numpy array?
  19. Python range() and zip() object type
  20. How do I merge multiple lists into one list? [duplicate]
  21. How can I format a list to print each element on a separate line in python? [duplicate]
  22. Group list by values [duplicate]
  23. Python: filtering lists by indices
  24. What are dict_keys, dict_items and dict_values?
  25. Ordered intersection of two lists in Python
  26. What to consider before subclassing list?
  27. How do I send list of dictionary as Body parameter in FastAPI?
  28. What is the cost/ complexity of insert in list at some location?
  29. Nested lambda statements when sorting lists
  30. Check list monotonicity

Leave a Comment