How to delete unique items in an array

[akadeco]

Hi

I need to write a program and part it's functionality is to delete unique items in an array. That is, delete items in the array that only occur once.

I also need to delete the first occurrence of repeated items, and I'm pretty sure the solution to these two will go hand in hand.

Thanks

akadeco

[bvdet]

akadeco,

Are you asking for help with your assignment? We can't help until you show some effort to solve this yourself.

BV
Moderator

[kudos]

(I guess the assignment is too small to be a school assignment)

a = [1,2,3,4,3,4,4,4,5,6]
b = {}
i = 0
for c in range(len(a)):
 if(b.has_key(a[i]) == False):
  b[a[i]] = 1
  a.remove(a[i])
 else: 
  i+=1
print a
 

-kudos


@akadeco

[bvdet]

Here's another way that creates a new list.

>>> a = [1,2,3,4,3,4,4,4,5,6]
>>> b = []
>>> for j, item in enumerate(a):
...     if a.count(item) > 1 and j > a.index(item):
...         b.append(item)
...         
>>> b
[3, 4, 4, 4]
>>> 

[kudos]

a = [1,2,3,4,3,4,4,4,5,6]
b=[]
for c in a:
 if(a.count(c) >=2 and b.count(c) < a.count(c)-1):
  b.append(c)
print b 
 

Can we avoid using the list 'b'?

-kudos

[bvdet]

With a list comprehension:

>>> a = [item for j, item in enumerate(a) if a.count(item) > 1 and j > a.index(item)]
>>> a
[3, 4, 4, 4]
>>> 

[akadeco]

@Kudos thank you so much that is exactly what I needed!

Thank you all for your swift replies