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# Unique In Order

## [Unique In Order](https://www.codewars.com/kata/54e6533c92449cc251001667)

Implement the function unique\_in\_order which takes as argument a sequence and returns a list of items without any elements with the same value next to each other and preserving the original order of elements.

For example:

```cpp
uniqueInOrder("AAAABBBCCDAABBB") == {'A', 'B', 'C', 'D', 'A', 'B'}
uniqueInOrder("ABBCcAD")         == {'A', 'B', 'C', 'c', 'A', 'D'}
uniqueInOrder([1,2,2,3,3])       == {1,2,3}
```

```javascript
uniqueInOrder('AAAABBBCCDAABBB') == ['A', 'B', 'C', 'D', 'A', 'B']
uniqueInOrder('ABBCcAD')         == ['A', 'B', 'C', 'c', 'A', 'D']
uniqueInOrder([1,2,2,3,3])       == [1,2,3]
```

```python
unique_in_order('AAAABBBCCDAABBB') == ['A', 'B', 'C', 'D', 'A', 'B']
unique_in_order('ABBCcAD')         == ['A', 'B', 'C', 'c', 'A', 'D']
unique_in_order([1,2,2,3,3])       == [1,2,3]
```

```ruby
unique_in_order('AAAABBBCCDAABBB') == ['A', 'B', 'C', 'D', 'A', 'B']
unique_in_order('ABBCcAD')         == ['A', 'B', 'C', 'c', 'A', 'D']
unique_in_order([1,2,2,3,3])       == [1,2,3]
```

```haskell
uniqueInOrder "AAAABBBCCDAABBB" == "ABCDAB"
uniqueInOrder "ABBCcAD"         == "ABCcAD"
uniqueInOrder [1,2,2,3,3]       == [1,2,3]
```

```
unique_in_order("AAAABBBCCDAABBB") == ['A', 'B', 'C', 'D', 'A', 'B']
unique_in_order("ABBCcAD")         == ['A', 'B', 'C', 'c', 'A', 'D']
unique_in_order([1,2,2,3,3])       == [1,2,3]
```

## Solutions

### 🐍 Python

```python
def unique_in_order(iterable):
    return [] if not iterable else [ i for n, i in enumerate(iterable) if n == 0 or i != iterable[n-1] ]
```