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# Learning Python-Basic course: Day 21, Summary of the week and dictionary exercises.

Aatmaj
I'm a Computer Science enthusiast with a keen interest in Maths. I like to tinker with things around me & build projects on my own. I like to play musical instruments & practise Sahaja Yoga meditation

## Today we will do more questions related to dictionaries for a thorough revision. In the process, we also will learn a few methods related to dictionaries.

Summary of the week-

• Day 18 We learnt about dictionaries. We checked out one example which covered many inbuilt functions related to dictionaries.
• Day 19 We practiced a few questions on dictionaries and had quite a thorough practice of dictionaries in Python. We did programs to fuse two separate lists to a single dictionary, paired out even numbers and made fancy dictionaries using for loops.
• Day 20 We learnt about hashtables and how to create them using dictionaries. We tried out simple and chained hashtables and worked out information retrieval using them.

## Sample question-Concatenate two dictionaries.

We will now fuse two dictionaries to create a new one using the `update()` method

``````a={1:10, 2:20}
b={3:30, 4:40}
c={}
for i in (a,b):
#for every element in dictionary a AND dictionary b,
c.update(i)
#update the dictionary to include these values.
print(c)
``````

output-

``````{1: 10, 2: 20, 3: 30, 4: 40}
``````

Conflict resolution- In case both the dictionaries have a same key, in that case the last value is held true by the `update()` method.

``````a={1:10, 2:20}
b={3:30, 4:40 , 2:60}
c={}
d={}
for i in (a,b):
c.update(i)
print(c)
for i in (b,a):
d.update(i)
print(d)
``````
``````{1: 10, 2: 60, 3: 30, 4: 40}
{1: 10, 2: 20, 3: 30, 4: 40}
``````

## Editing keys.

I know what you all must be thinking. Keys are non-mutable right?
Yes. they are. but here is a cleaver trick

``````a = {
"a":1,
"b":2,
"c":3,
"e":4
}
# Replace 'e' by 'd'

a["d"] = a.pop("e")
print(a)
``````
``````{'b': 2, 'a': 1, 'c': 3, 'd': 4}
``````

Today there are no exercises from my side..😃...But wait!😒 I am providing a reference link for taking on a dictionary quiz to clear all your concepts!😋
Dictionary quiz by PYnative
The quiz contains 14 Questions. 14/14 is the target

✌️So friends that's all for now. 😊 Hope you all are having fun.😎 Please let me know in the comment section below 👇. And don't forget to like the post if you did. 😍 I am open to any suggestions or doubts. 🤠 Just post in the comments below or gmail me. 😉

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