Python dictionary understanding tutorial | Dict type in Python part 17

Python dictionary understanding tutorial | Dict type in Python part   17

Python dictionary understanding tutorial
Learn all about the understanding of Python dictionaries: how you can use it, to create dictionaries, loops (nested) with filters (), filters () and comm (), ... or lambda functions. To replace for!
Dictionaries (or dictators in Python) are a way of storing elements similar to yours in a Python list. But, instead of accessing elements using its index, you assign it a fixed key and access the element using the key. The behavior you now do is a "key-value" pair, sometimes a more appropriate data structure for many problems rather than a simple list. You often have to deal with dictionaries when doing data science, which makes the dictionary a skill you want to master.

In this tutorial:

First you will see what Python Dictionary really is and how you can use it effectively.
Next, you'll learn about the Python dictionary: you'll see what it is, why it's important and how it can serve as an alternative to loop and lamda functions.
You will learn how to add dictionaries to dictionaries: if you work with terms, many terms and if-else statements.
Finally, you will see what a nested dictionary is, how you can use it and how you can potentially write it with a loop.
let's get started...

Python dictionary

Python is a collection of objects accessed by a specific key instead of a dictionary index. what does this mean?

Imagine a dictionary in the real world ... When you need to see the meaning of a word, you try to find the meaning using the word and not the possible index of the word. The Python dictionary works with the same concept, the meaning of the word you are looking for is the key and the meaning of the word is the value, you do not need to know the index of the word in a dictionary to find its meaning.

Note: Keys can be washed in a dictionary.

Hashing is the process of running an item through a special type of function. This function is called the "hash function". This hash function returns a unique output for a unique input value. Integers, floating point numbers, strings, tuples, and froznets are feasible. While there are no lists, acronyms and sets other than Frazenset. Hashing is a somewhat complex subject and is only the basic concept behind hashing.

You can initialize a dictionary in Python like this:

a = {'apple': 'fruit', 'beet': 'vegetable', 'cake': 'dessert'}
[['Donut'] = 'snack'
Print (an ['apple'])
The fruit
Print (a [0])
-------------------------------------------------- -------------------------

KeyError Traceback (most recent call last)

in <ipython-input-9-00d4a978143a> <module> ()
----> 1 print (a [0])


Keyer: 0
Note that the line of code above gives you an error message because the key '0' is not present there.

A dictionary can contain any type of data. Look for some more examples of dictionaries to hang it:

a = {'one': 1, 'two': 'to', 'three': 3.0, 'four': [4-0.0%}
Print (a)
{[Four ': [4, 4.0],: two': [from ',: three': 3.0, 'one': 1}
# Update a dictionary
[a '' a '] = 1.0
Print (a)
{[Four ': [4, 4.0],: two': [from ',: three': 3.0, 'one': 1.0}

#Delete an element

Dale a ['one']
Print (a)
{[Four ': [4, 4.0],: two': [from ',: three': 3.0}
# Remove all elements in the dictionary
A clean ()
Print (a)
{}

# Remove dictionary

Dale a
Print (a)
-------------------------------------------------- -------------------------

NameError Traceback (Most Recent Call Last)

<module> () in <ipython-input-12-701c9d6596da>
1 dell a #Deletes Dictionary
----> 2 prints (one)


NameError: Name 'a' is not defined
It is important to remember that a key must be unique in a dictionary, no duplicates are allowed. However, in the case of duplicate keys instead of giving an error, Python will validate the last instance of the key and ignore the first key-value pair. Check it out for yourselves:

sweet_dict = {'a1': 'cake', 'a2': 'cookie', 'a1': 'icecream'}
Print (sweet_dict ['a1'])
Ice Cream
If you want to know more about dictionaries in Python, see this tutorial.

Understand python dictionary

Dictionary comprehension is a method of converting one dictionary into another. During this change, items within the original dictionary can be included conditionally in the new dictionary and each item can be modified as needed.

A good list understanding can make your code more expressive and thus, easier to read. The key to making sense is not to let them get so complicated that your head turns around when you try to understand what they are actually doing. Keeping the idea of ​​"easy to read" alive.

The way to make sense of a dictionary in Python is to be able to access the key objects and value objects of a dictionary.

How can this be done?

Python has you covered! You can use the underlying methods for just that:

Dict 1 = {'a': 1, 'b': 2, 'c': 3, 'd':