Enumerate() Function in Python: Loop, Tuple, String (Example)

Details

What is Python Enumerate?

Python Enumerate() is a buit-in function available with the Python library. It takes the given input as a collection or tuples and returns it as an enumerate object. The Python Enumerate() command adds a counter to each item of the iterable object and returns an enumerate object as an output string.

In this Enumerate Python tutorial, you will learn:

Syntax of Python enumerate()

enumerate(iterable, startIndex)

Parameters

Three parameters are:

However, If startIndex is not specified, the count will start from 0.

ReturnValue:

It will return an iterableobject, with countvalue to each of the items to the iteratorobject given as input.

Enumerate() in Python Example

Enumerate method comes with an automatic counter/index to each of the items present in the Enumerate list in Python. The firstindex value will start from 0. You can also specify the startindex by using the optional parameter startIndex in enumerate.

Example

In the code below, mylist is the list given to Enumerate function in Python. The list() function is used to display the Enumerate Python output.

Note: There is no startIndex used hence the index for the firstitem will start from 0.

The output from enumerate will be in the following manner: 

(0, item_1), (1, item_2), (2, item_3), … (n, item_n)

File: python_enumerate.py 

mylist = ['A', 'B' ,'C', 'D']
e_list = enumerate(mylist)
print(list(e_list))

Output: 

[(0, 'A'), (1, 'B'), (2, 'C'), (3, 'D')]

UsingEnumerate() on a list with startIndex

In the below example, the startindex given as 2.The index of the firstitem will start from the given startindex.

Example:

In the example below, mylist is the list given to enumerate. The list() function is used to display the enumerate output. 

mylist = ['A', 'B' ,'C', 'D']
e_list = enumerate(mylist,2)
print(list(e_list))

Output: 

[(2, 'A'), (3, 'B'), (4, 'C'), (5, 'D')]

Looping Over an Enumerate object

The example shows enumerating over an object with and without startIndex.

Example: 

mylist = ['A', 'B' ,'C', 'D']

for i in enumerate(mylist):
  print(i)
  print("\n")

print("Using startIndex as 10")    

for i in enumerate(mylist, 10):
  print(i)
  print("\n")

Output: 

(0, 'A')
(1, 'B')
(2, 'C')
(3, 'D')

Using startIndex as 10
(10, 'A')
(11, 'B')
(12, 'C')
(13, 'D')

Enumerating a Tuple

In the below example, you can use a tuple inside an enumerate. You can also use a startIndex, and the key to each item will start from the startIndexgiven.

By default, the startIndex is 0. There, hence you see key as 0 for items A and 1 for B and so on.

Example: 

my_tuple = ("A", "B", "C", "D", "E")
for i in enumerate(my_tuple):
  print(i)

Output:

(0, 'A')
(1, 'B')
(2, 'C')
(3, 'D')
(4, 'E')

Enumerating a String

In Python, the string is an array, and hence you can loop over it. If you pass a string to enumerate(), the output will show you the index and value for each character of the string.

Example: 

my_str = "gtupapers "
for i in enumerate(my_str):
  print(i)

Output: 

(0, 'G')
(1, 'u')
(2, 'r')
(3, 'u')
(4, '9')
(5, '9')

Enumerate a dictionary

In Python, a dictionary is listed in curly brackets, inside these curly brackets, the values are declared.

Each element is a key/value pair and separated by commas. You can use a dictionary inside a enumerate() and see the output. 

my_dict = {"a": "PHP", "b":"JAVA", "c":"PYTHON", "d":"NODEJS"}
for i in enumerate(my_dict):
  print(i)

Output: 

(0, 'a')
(1, 'b')
(2, 'c')
(3, 'd')

Advantages of using Enumerate

Here, are pros/benefits of using Enumerate in Python:

Summary

 

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