How to remove items from a list while iterating?

by

You can use a list comprehension to create a new list containing only the elements you don’t want to remove:

somelist = [x for x in somelist if not determine(x)]

Or, by assigning to the slice somelist[:], you can mutate the existing list to contain only the items you want:

somelist[:] = [x for x in somelist if not determine(x)]

This approach could be useful if there are other references to somelist that need to reflect the changes.

Instead of a comprehension, you could also use itertools. In Python 2:

from itertools import ifilterfalse
somelist[:] = ifilterfalse(determine, somelist)

Or in Python 3:

from itertools import filterfalse
somelist[:] = filterfalse(determine, somelist)

More Related Contents:

  1. how to can i go over a file twice?
  2. Python Error with iteration, for loop
  3. Does pandas iterrows have performance issues?
  4. Are for-loops in pandas really bad? When should I care?
  5. Iterating through a range of dates in Python
  6. Is there a way in Pandas to use previous row value in dataframe.apply when previous value is also calculated in the apply?
  7. Iterating each character in a string using Python
  8. Loop that also accesses previous and next values
  9. recursive iteration through nested json for specific key in python
  10. Grouping / clustering numbers in Python
  11. How to loop over grouped Pandas dataframe?
  12. Is there a better way to iterate over two lists, getting one element from each list for each iteration? [duplicate]
  13. Modify a list while iterating
  14. How to recursively find specific key in nested JSON?
  15. What exactly is Python’s iterator protocol?
  16. How do I loop through a list by twos? [duplicate]
  17. Iterate over all combinations of values in multiple lists in Python [duplicate]
  18. Converting a list of tuples into a dict
  19. How to loop backwards in python? [duplicate]
  20. Python using enumerate inside list comprehension
  21. How to transform string of space-separated key,value pairs of unique words into a dict
  22. How to iterate through a list of dictionaries in Jinja template?
  23. Iteration over list slices
  24. Converting for loops to while loops in python
  25. “For” loop first iteration
  26. Set iteration order varies from run to run
  27. Spark iteration time increasing exponentially when using join
  28. Python: Adding element to list while iterating
  29. range(len(list)) or enumerate(list)? [duplicate]
  30. Iterate over a string 2 (or n) characters at a time in Python

Leave a Comment