c in enumerate meaning python code example

Example 1: what does enumerate do in python

The enumerate() function assigns an index to each item in an 
iterable object that can be used to reference the item later. 
What does enumerate do in Python? It makes it easier to keep 
track of the content of an iterable object.

Example 2: what is enumerate in python

np.r_[1:10, 15, 17, 50:100]

array([ 1,  2,  3,  4,  5,  6,  7,  8,  9, 15, 17, 50, 51, 52, 53, 54, 55,
       56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72,
       73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,
       90, 91, 92, 93, 94, 95, 96, 97, 98, 99])