a = [9,8,2,3,8,3,5]
How to remove 2nd occurrence of 8 without removing 1st occurrence of 8 using remove().
a = [9,8,2,3,8,3,5]
How to remove 2nd occurrence of 8 without removing 1st occurrence of 8 using remove().
It's not clear to me why this specific task requires a loop:
array = [9, 8, 2, 3, 8, 3, 5]
def remove_2nd_occurance(array, value):
''' Raises ValueError if either of the two values aren't present '''
array.pop(array.index(value, array.index(value) + 1))
remove_2nd_occurance(array, 8)
print(array)
Here's a way you can do this using itertools.count along with a generator:
from itertools import count
def get_nth_index(lst, item, n):
c = count(1)
return next((i for i, x in enumerate(lst) if x == item and next(c) == n), None)
a = [9,8,2,3,8,3,5]
indx = get_nth_index(a, 8, 2)
if indx is not None:
del a[indx]
print(a)
# [9, 8, 2, 3, 3, 5]
remove() removes the first item from the list which matches the specified value. To remove the second occurrence, you can use del instead of remove.The code should be simple to understand, I have used count to keep track of the number of occurrences of item and when count becomes 2, the element is deleted.
a = [9,8,2,3,8,3,5]
item = 8
count = 0
for i in range(0,len(a)-1):
if(item == a[i]):
count = count + 1
if(count == 2):
del a[i]
break
print(a)
This one if you need to delete second and following occurrence of a target item:
# deleting second and following occurrence of target item
a = [9,8,2,3,8,3,5]
b = []
target = 8 # target item
for i in a:
if i not in b or i != target:
b.append(i)
a=b
print(a)
# [9, 8, 2, 3, 3, 5]
If you need to delete second and following occurrence for any item:
# deleting any second and following occurence of each item
a = [9,8,2,3,8,3,5]
b = []
for i in a:
if i not in b:
b.append(i)
a=b
print(a)
# [9, 8, 2, 3, 5]
Now, when you need to delete only second occurrence of target item:
# deleting specific occurence of target item only (use parameters below)
a = [9,8,2,3,8,3,5,8,8,8]
b = []
# set parameters
target = 8 # target item
occurence = 2 # occurence order number to delete
for i in a:
if i == target and occurence-1 == 0:
occurence = occurence-1
continue
elif i == target and occurence-1 != 0:
occurence = occurence-1
b.append(i)
else:
b.append(i)
a=b
print(a)
# [9, 8, 2, 8, 3, 5, 8, 8, 8]
python code to remove 2nd occurrence
ls = [1, 2, 3, 2]
index = ls.index(2, 0)
lss = ls[index + 1:]
lss.remove(2)
print(ls[:index + 1]+lss)
list1=["L",1,"L",2,"L"]
print(list1)
print(list1.index("L",1))
list1.pop(2)
print(list1)