Posted By: Anonymous
I want to remove a value from a list if it exists in the list (which it may not).
a = [1, 2, 3, 4] b = a.index(6) del a[b] print(a)
The above case (in which it does not exist) shows the following error:
Traceback (most recent call last): File "D:zjm_codea.py", line 6, in <module> b = a.index(6) ValueError: list.index(x): x not in list
So I have to do this:
a = [1, 2, 3, 4] try: b = a.index(6) del a[b] except: pass print(a)
But is there not a simpler way to do this?
To remove an element’s first occurrence in a list, simply use
>>> a = ['a', 'b', 'c', 'd'] >>> a.remove('b') >>> print(a) ['a', 'c', 'd']
Mind that it does not remove all occurrences of your element. Use a list comprehension for that.
>>> a = [10, 20, 30, 40, 20, 30, 40, 20, 70, 20] >>> a = [x for x in a if x != 20] >>> print(a) [10, 30, 40, 30, 40, 70]