[Solved-3 Solutions] Is there a simple way to delete a list element by value?
Error Description:
a=[1,2,3,4]
b=a.index(6)
del a[b]
print a click below button to copy the code. By - python tutorial - team
- 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 click below button to copy the code. By - python tutorial - team
Solution 1:
- To remove an element's first occurrence in a list, simply use list.remove:
>>> a = ['a', 'b', 'c', 'd']
>>> a.remove('b')
>>> print a
['a', 'c', 'd'] click below button to copy the code. By - python tutorial - team
- Mind that it does not remove all occurrences of your element. Use a list comprehension for that.
>>> a = [1, 2, 3, 4, 2, 3, 4, 2, 7, 2]
>>> a = [x for x in a if x != 2]
>>> print a
[1, 3, 4, 3, 4, 7] click below button to copy the code. By - python tutorial - team
Solution 2:
- 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) click below button to copy the code. By - python tutorial - team
- or:
try:
a.remove(c)
except ValueError:
pass click below button to copy the code. By - python tutorial - team
Solution 3:
- You can do
a=[1,2,3,4]
if 6 in a:
a.remove(6) click below button to copy the code. By - python tutorial - team
- but above need to search 6 in list a 2 times, so try except would be faster
try:
a.remove(6)
except:
pass