Here are a few title options, keeping in mind the question-answer format and the article\'s focus on grouping data pairs in Python: Option 1 (General): * How to Group Data Pairs in Python Based on S

Python Group By

Problem:

Given a set of data pairs, group them based on the value at a specified index and convert them into a desired format.

Solution:

To efficiently group data pairs by their type, follow these steps:

Step 1: Create a Dictionary

Create a dictionary using the defaultdict from the collections module, where the keys are the types and the values are lists of values:

<code class="python">from collections import defaultdict

res = defaultdict(list)
for v, k in input:
    res[k].append(v)</code>

Step 2: Convert Dictionary to Desired Format

Convert the created dictionary into a list of dictionaries with the desired format:

<code class="python">result = [{'type': k, 'items': v} for k,v in res.items()]</code>

Additional Considerations:

• To preserve the original order of the keys in Python versions before 3.7, use the OrderedDict from the collections module.
• For Python versions 3.7 and above, a regular dictionary maintains the insertion order.

Alternative Approach Using **itertools.groupby()**:

An alternative approach involves using the itertools.groupby function, but requires the input data to be sorted terlebih dahulu.

<code class="python">import operator as itemgetter
import itertools

sorted_input = sorted(input, key=itemgetter(1))
groups = itertools.groupby(sorted_input, key=itemgetter(1))
result = [{'type': k, 'items':[x[0] for x in v]} for k, v in groups]</code>

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