**[Itertools](https://www.educative.io/answers/what-are-itertools-in-python)** is a module in Python that enables fast, and memory-efficient iteration over iterable data structures. 

The module has a number of functions that construct and return iterators. One such function is the `groupby` function. This function groups data from the given iterable based on the key that is computed by a function. 
# 
## Syntax

```py
zip_groupby(iterable, key=None)
```
The function takes two arguments: `iterables` and `fill value`.

* **`iterable`** is the data structure over which you want to iterate. It can be of any type such as a list, tuple, or dictionary.

* **`key`** is a function that computes the key for each element in `iterable`. 

## Return value

The function returns an iterable object with consecutive keys and groups.

## Example

* In the following example, we first create an `input_list` that contains some universities and the programs offered.
* We create the `key_func` function to compute the key based on which we will group the data.
* `grouped_data` is returned by the `groupby` method which takes in the `input_list` and `key_func` to group data.
* We iterate over the `grouped_data` and print the key and its corresponding value.


import itertools

input_list = [("University", "Harvard"),("University","MIT"),("University","UC Berkley"),("Program","Computer Science"),("Program", "Marine Biology")]
key_func = lambda x: x[0]
grouped_data = itertools.groupby(input_list,key_func)
for key,value in grouped_data:
  print(key,":",list(value))

What is itertools.groupby in Python?

Groups data from iterables based on a key function, returning consecutive keys and groups.