• 
  
  import operator
  
  
• 
  
  from functools import reduce
  
  
• 
  
  a = [[1,2,3], [4,6], [7,8,9,8]]
  
  
• 
  
  print(reduce(operator.add, a))
  
  
• 
  
  [1, 2, 3, 4, 6, 7, 8, 9, 8]
  
  
  

• 
  
  a = [[1,2,3], [5, 8], [7,8,9]]
  
  
• 
  
  l=[]
  
  
• 
  
  for m in range(0,3):
  
  
• 
  
      for i in a[m]:
  
  
• 
  
          l.append(i)
  
  
• 
  
  print(l)
  
  
• 
  
  [1, 2, 3, 5, 8, 7, 8, 9]
  
  
  

• 
  
  from itertools import chain
  
  
• 
  
  b=[[1,2,3], [5,8], [7,8,9]]
  
  
• 
  
  c=list(chain(*b))
  
  
• 
  
  print(c)
  
  
• 
  
  [1, 2, 3, 5, 8, 7, 8, 9]
  
  
  

• 
  
  a=[[1,2,3], [5,8], [7,8,9]]
  
  
• 
  
  a= eval('['+str(a).replace(' ','').replace('[','').replace(']','')+']')
  
  
• 
  
  print(a)
  
  
• 
  
  [1, 2, 3, 5, 8, 7, 8, 9]
  
  
  

• 
  
  def flatten(a):
  
  
• 
  
      if not isinstance(a, (list, )):
  
  
• 
  
          return [a]
  
  
• 
  
      else:
  
  
• 
  
          b = []
  
  
• 
  
          for item in a:
  
  
• 
  
              b += flatten(item)
  
  
• 
  
      return b
  
  
  

• 
  
  if __name__ == '__main__':
  
  
• 
  
      a = [[[1,2],3],[4,[5,6]],[7,8,9]]
  
  
• 
  
      print(flatten(a))
  
  
• 
  
  [1, 2, 3, 4, 5, 6, 7, 8, 9]
  
  
  

• 
  
  ab = [[1,2,3], [5,8], [7,8,9]]
  
  
• 
  
  print([i for item in ab for i in item])
  
  
• 
  
  [1, 2, 3, 5, 8, 7, 8, 9]
  
  
  

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