Remove sequential repeats from python list

Question

I have a list of tuples. First element is index. I need to delete tuples which has subsequent indexes only leaving first tuple from each sequence:

In:
[
  [0, 100],
  [1, 200],
  [5, 600],
  [6, 300],
  [7, 800],
  [9, 300],
  [11, 100],
  [14, 300],
]

Out:
[
  [0, 100],
  [5, 600],
  [9, 300],
  [11, 100],
  [14, 300],
]

Asked By: Boppity Bop

||

Source

Answer 1

Using a simple loop (and assuming l the input list):

prev = -float('inf')
out = []
for x in l:
    if x[0]>prev+1:
        out.append(x)
    prev=x[0]

output: [[0, 100], [5, 600], [9, 300], [11, 100], [14, 300]]

Answered By: mozway

Answer 2

well you need to group the data in based on their difference ie it should be 1. and then from that list add first element in final result.

data = [
  [0, 100],
  [1, 200],
  [5, 600],
  [6, 300],
  [7, 800],
  [9, 300],
  [11, 100],
  [14, 300],
]

result =[]
data2 =  sorted(data, key = lambda x:x[0])
tmp = []
for a in data2:
    if not tmp:
        tmp.append(a)
    else:
        val = tmp[-1]
        if a[0]-val[0] ==1:
            tmp.append(a)
        else:
            result.append(tmp[0] )
            tmp =[a]
if tmp:
    result.append(tmp[0])
print(result)

output

[[0, 100], [5, 600], [9, 300], [11, 100], [14, 300]]

Answered By: sahasrara62

Remove sequential repeats from python list

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