a = [1, 2, 3, 4] b = a.index(6) del a[b] print a
The above shows the following error:
Traceback (most recent call last): File "D:\zjm_code\a.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]
Usually Python will throw an Exception if you tell it to do something it can't so you'll have to do either:
if c in a: a.remove(c)
try: a.remove(c) except ValueError: pass
An Exception isn't necessarily a bad thing as long as it's one you're expecting and handle properly.