What is the purpose of the 'enumerate()' function in Python?

In this article, we will learn about enumerate() function and the purpose of “enumerate()” function in Python.

What is the enumerate() function?

Python’s enumerate() function accepts a data collection as a parameter and returns an enumeration object.

The enumeration object is returned in the form of key-value pairs. The key is the index corresponding to each item, and the value is the items.

grammar

enumerate(iterable, start)

parameter

• iterable - The passed in data collection can be returned as an enumeration object, called iterable

• start - As the name suggests, the starting index of the enumeration object is defined by start. If we omit this value, it will consider the first index to be zero since zero is the default value here

Usage of enumerate() function in Python

When to use the enumerate() function?

If you need the index of the iterated value, use the enumerate() function.

how to use?

The enumeration function assigns the index of each iterable value to the list.

Why use the enumerate() function?

When using iterators, we always need to know how many iterations have been completed, that is, the number of iterations.

However, we have a Pythonic way to determine the necessary number of iterations. The syntax is as follows -

enumerate(iterable, start)

How to use enumerate() function in Python?

It is important to note which data type will be used to store the enumeration object after returning.

Example

The following program uses the enumerate() function on a list to get a list of tuples with indexes -

# input list
inputList = ["hello", "tutorialspoint", "python", "codes"]

# getting the enumerate object of the input list
enumerate_obj = enumerate(inputList)
print(enumerate_obj)

# converting the enumerate object into a list and printing it
print(list(enumerate_obj))

Output

When executed, the above program will generate the following output -

<enumerate object at 0x7f4e56b553c0>
[(0, 'hello'), (1, 'tutorialspoint'), (2, 'python'), (3, 'codes')]

Use the second parameter "starting index" of the enumerate() function

Example

The following program shows how to apply the enumerate() function to a list containing a second argument -

# input list
inputList = ["hello", "tutorialspoint", "python", "codes"]

# getting the enumerate object starting from the index 15
enumerate_obj = enumerate(inputList, 15)

# converting the enumerate object into the list and printing it
print(list(enumerate_obj))

Output

When executed, the above program will generate the following output -

[(15, 'hello'), (16, 'tutorialspoint'), (17, 'python'), (18, 'codes')]

In the above example, we added 15 as the second parameter in the enumerate() function. The second parameter will indicate the starting index of the key (index) in the enumerator object, so we can see in the output that the first index is 15, the second index is 16, and so on.

Python code for looping through enumerated objects

Example

The following program shows how to use a for loop to iterate through an enumeration object and print each element in it -

# input list
inputList = ["hello", "tutorialspoint", "python", "codes"]

# getting the enumerate object
enumerate_obj = enumerate(inputList)

# traversing through each item in an enumerate object
for i in enumerate_obj:

    # printing the corresponding iterable item
    print(i)

Output

When executed, the above program will generate the following output -

(0, 'hello')
(1, 'tutorialspoint')
(2, 'python')
(3, 'codes')

Use the enumerate() function on tuples

Example

The following program shows how to use the enumerate() function on a given input tuple -

# input tuple
inputTuple = ("hello", "tutorialspoint", "python", "codes")

# getting the enumerate object of the input tuple
enumerate_obj = enumerate(inputTuple)
print(enumerate_obj)

# converting the enumerate object into the list and printing it
print(list(enumerate_obj))

Output

When executed, the above program will generate the following output -

<enumerate object at 0x7fec12856410>
[(0, 'hello'), (1, 'tutorialspoint'), (2, 'python'), (3, 'codes')]

Using the enumerate() function on strings

Iterate over string data using enumeration functions to determine the index of each character.

Example

The following program shows how to use the enumerate() function on a given input string -

# input string
inputString = "python"

# getting the enumerate object of an input string
enumerate_obj = enumerate(inputString)

# converting the enumerate object into the list and printing it
print(list(enumerate_obj))

Output

When executed, the above program will generate the following output -

[(0, 'p'), (1, 'y'), (2, 't'), (3, 'h'), (4, 'o'), (5, 'n')]

Use another parameter in the enumerate() function

Example

The following program shows how to use another parameter in the enumerate() function -

input_data = ('Hello', 'TutorialsPoint', 'Website')
for count, dataValue in enumerate(input_data,start = 50):
   print(count, dataValue)

Output

When executed, the above program will generate the following output -

(50, 'Hello')
(51, 'TutorialsPoint')
(52, 'Website')

• Enumerate is a Python built-in function that returns an enumeration object.

• This function returns an enumeration object.

• To pass an iterable object to an enumeration function, first try to retrieve the data from the enumeration object and then convert it to list(). As a result, as shown in the example above, it returns a list of tuples along with the iteration index.

in conclusion

This article introduces the application of Python enumerate() function in detail. We also learned how to use it with various Python data types and iteration. Additionally, we also learned how to modify the starting count or index of the enumerate() function.

The above is the detailed content of What is the purpose of the 'enumerate()' function in Python?. For more information, please follow other related articles on the PHP Chinese website!