Inverts a dictionary with non-unique hashable values.

👉Create a collections.defaultdict with list as the default value for each key.

👉Use dictionary.items() in combination with a loop to map the values of the dictionary to keys using dict.append().

👉Use dict() to convert the collections.defaultdict to a regular dictionary.

CODE:

from collections import defaultdict

def collect_dictionary(obj):
inv_obj = defaultdict(list)
for key, value in obj.items():
inv_obj[value].append(key)
return dict(inv_obj)

Example:

ages = {
'Peter': 10,
'Isabel': 10,
'Anna': 9,
}
collect_dictionary(ages)

Output: { 10: ['Peter', 'Isabel'], 9: ['Anna'] }

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Walrus operator:

The Walrus or := operator is one of the latest additions to python 3.8.
It is an assignment operator that lets you assign value to a variable within an expression like conditional statements, loops, etc.


Example

If we want to check and print the length of a list:

Mylist = [1,2,3]
if(l := len(mylist) > 2)
print(l)

Output

3

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What Is FastAPI?

FastAPI is a modern, high-performance web framework for building APIs with Python based on standard type hints.


It has the following key features:

👉Fast to run: It offers very high performance, on par with NodeJS and Go, thanks to Starlette and pydantic.

👉Fast to code: It allows for significant increases in development speed.

👉Reduced number of bugs: It reduces the possibility for human-induced errors.

👉Intuitive: It offers great editor support, with completion everywhere and less time debugging.

👉Straightforward: It’s designed to be uncomplicated to use and learn, so you can spend less time reading documentation.

👉Short: It minimizes code duplication.

👉Robust: It provides production-ready code with automatic interactive documentation.

👉Standards-based: It’s based on the open standards for APIs, OpenAPI and JSON Schema.

You can use this instead of Django and Flask

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Difference between list and tuple in python

🔸List is mutable ( you can modify the original list) and it's values are written in sqare brackets [ ]

🔸Tuple is immutable ( you can't modify it) and it's values are written in parentheses ( ) delimited by comma( , )

🔸To convert list to tuple - we use tuple() function
list1 = [1,2,3]
print(tuple(list1)) Output : (1,2,3)

🔸 For single element list
list1 = [1]
print(tuple(list1)) Output : (1, )

▪️a tuple is a tuple because of comma not because of parentheses


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To shuffle pandas DataFrame df (in a reproducible way):

df = df.sample(frac=1, random_state=123).reset_index(drop=True)

Alternatively, you can use sklearn.utils.shuffle().

#pandas

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Do you know abou .strip()

From the above example you can see that it removed all the characters mentioned in .strip('comw.') and returns the remaining string


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Useful Pandas🐼 method you should definitely know

✅ head()
✅ info()
✅ fillna()
✅ melt()
✅ pivot()
✅ query()
✅ merge()
✅ assign()
✅ groupby()
✅ describe()
✅ sample()
✅ replace()
✅ rename()


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💡 Python Tip: Do you know Ellipsis(...) can be used as a placeholder in Python, just like a 𝘱𝘢𝘴𝘴 statement?

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Summarize any website content in just a few lines of Python code.

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💡 Python Life Hack: Do you know you can copy the files from a computer to a mobile phone 📱 without any cable using Python 🐍 ?

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