I finally understood why my Python loop kept skipping items

I was writing a script to remove all zeros from a list of numbers. I used a 'for' loop that checked each item and used '.remove()' if it was zero. After running it, some zeros were still there. I spent an hour confused until I realized that removing an item changes the list's length and index positions while the loop is running, so it skips the next item. I fixed it by creating a new list instead. Has anyone else run into this classic beginner trap?

2 comments

2 Comments

oliver_torres44d ago

Classic. Did you try using a while loop instead? Iterating backwards from the end of the list also fixes the index shift problem.

the_drew4d ago

My brain defaults to for loops, honestly.