11.3. Enumerate#

  • Adds number to the list

  • Counter

  • Used when you need counter or positions or Indexes

11.3.1. Syntax#

  • enumerate(list)

    • Takes list

    • Returns tupple by default (iterable so has to be converted explicitly)

list1=['a','b']

enumerate(list1) # returns iterable obj <> which is tuple by default but can be converted to list as well

<enumerate at 0x7f8ec20ce540>

print([i for i in enumerate(list1)])  # by default returns tupple we just returned i

print([(i,j) for i,j in enumerate(list1)]) # this is same thing as above

#print([i,j for i,j in enumerate(list1)])   # this will give error because you are explicitly returning two vars

print([[i,j] for i,j in enumerate(list1)]) # can be converted to list as well

[(0, 'a'), (1, 'b')]
[(0, 'a'), (1, 'b')]
[[0, 'a'], [1, 'b']]

11.4. Use case#

#All the if conditions can be applied since it is list comprehension

11.4.1. Getting even indexed values#

  • Note:It is based on index not actual values

list=[11,13,12,14,15,76,89]

11.4.2. Get the index only if index==even#

[(i,j) for i,j in enumerate(list) if i%2==0]

[(0, 11), (2, 12), (4, 15), (6, 89)]

11.4.3. Get the index only if value= 76#

[i for i,j in enumerate(list) if j==76]

[5]