Coding in Python: a comprehensive Beginners Guide to Learn the Realms of Coding in Python

Removing Pairs
When you don’t need a certain key-value pair, you can remove it easily. You
can apply the del statement to remove the key-value pair. All you have to do
is to mention the name of your dictionary and key. I will remove different
items from the dictionary I have created earlier on.
officeitems = {'printer' : 'HP', 'paper': 'A4', 'drafting pads': 'blank', 'scanner':
'hybrid', 'table': 'wood', 'table lights': 'LED'}
print(officeitems)
del officeitems['printer']
print(officeitems)
del officeitems['paper']
print(officeitems)
del officeitems['drafting pads']
print(officeitems)
del officeitems['scanner']

---

print(officeitems)
del officeitems['table']
print(officeitems)
del officeitems['table lights']
print(officeitems)
= RESTART: C:/Users/saifia computers/Desktop/sample.py
{'printer': 'HP', 'paper': 'A4', 'drafting pads': 'blank', 'scanner': 'hybrid', 'table':
'wood', 'table lights': 'LED'}
{'paper': 'A4', 'drafting pads': 'blank', 'scanner': 'hybrid', 'table': 'wood', 'table
lights': 'LED'}
{'drafting pads': 'blank', 'scanner': 'hybrid', 'table': 'wood', 'table lights': 'LED'}
{'scanner': 'hybrid', 'table': 'wood', 'table lights': 'LED'}
{'table': 'wood', 'table lights': 'LED'}
{'table lights': 'LED'}
{}
>>>
You can see that when all the pairs are removed, the result is an empty
dictionary. One important thing to keep in mind is that the del statement
removes a pair completely from the dictionary. Therefore, only use the del
statement when you are sure that you do not need a certain key-value pair.
A dictionary allows you to use the values in a print statement to display
certain messages.
officeitems = {'printer' : 'HP', 'paper': 'A4', 'drafting pads': 'blank', 'scanner':
'hybrid', 'table': 'wood', 'table lights': 'LED'}
print("I bought a printer by " + officeitems['printer'] + ".")
print("I also bought a scanner by " + officeitems['scanner'] + ".")
print("The paper if of the size " + officeitems['paper'] + ".")
print("The drafting pads are " + officeitems['drafting pads'] + ".")

---

= RESTART: C:/Users/saifia computers/Desktop/sample.py
I bought a printer by HP.
I also bought a scanner by hybrid.
The paper if of the size A4.
The drafting pads are blank.
>>>
I have used the print keyword in the code. Then I added the appropriate
statement to the code. After that came the part of the concatenation operator.
This is how you can use the values of a dictionary to display messages in
your code.
Looping
Just like we formed a loop through a list, we can form the same through a
dictionary as well. A Python dictionary may contain a few millions of key-
value pairs. As a dictionary carries big amounts of data, Python allows you to
create a loop through it to easily see each key-value pair and use it in a
program. In the first example, I will loop through each item in your
dictionary.
officeitems = {'printer' : 'HP', 'paper': 'A4', 'drafting pads': 'blank', 'scanner':
'hybrid', 'table': 'wood', 'table lights': 'LED'}
for key, value in officeitems.items():
print("\nThe Key: " + key)
print("The Value: " + value)
= RESTART: C:/Users/saifia computers/Desktop/sample.py
The Key: printer
The Value: HP
The Key: paper
The Value: A4
The Key: drafting pads
The Value: blank

---

The Key: scanner
The Value: hybrid
The Key: table
The Value: wood
The Key: table lights
The Value: LED
>>>
There is another method to display the values of each key-value pair. See the
following example.
officeitems = {'printer' : 'HP', 'paper': 'A4', 'drafting pads': 'blank', 'scanner':
'hybrid', 'table': 'wood', 'table lights': 'LED'}
for k, v in officeitems.items():
print("\nThe Key: " + k)
print("The Value: " + v)
= RESTART: C:/Users/saifia computers/Desktop/sample.py
The Key: printer
The Value: HP
The Key: paper
The Value: A4
The Key: drafting pads
The Value: blank
The Key: scanner
The Value: hybrid
The Key: table
The Value: wood
The Key: table lights
The Value: LED

---

>>>
One important thing to consider before moving on is the order in which
Python stores the key-value pairs. When you create and run a loop through a
dictionary, Python does not care about the order in which you had created the
dictionary. It only tracks down the keys and their respective values.
officeitems = {'printer' : 'Produced by HP', 'paper': 'A4 type', 'drafting pads':
'It is blank', 'scanner': 'it is hybrid', 'table': 'made of wood', 'table lights': 'They
are LED'}
for items, features in officeitems.items():
print(items.title() + " carries the following feature: " + features.title())
= RESTART: C:/Users/saifia computers/Desktop/sample.py
Printer carries the following feature: Produced By Hp
Paper carries the following feature: A4 Type
Drafting Pads carries the following feature: It Is Blank
Scanner carries the following feature: It Is Hybrid
Table carries the following feature: Made Of Wood
Table Lights carries the following feature: They Are Led
>>>
The code instructs Python to loop through the key-value pairs inside of the
dictionary. As the code loops through each pair, Python first stores each key
inside the variable named items. It stores each value inside the variable
named features. The same variables are then added to the print statement that
runs and displays related messages.
You can opt for looping through all the keys or values separately. For
example, sometimes you need to work just with the keys and only want to
display them. There is a way out. See the following example.
officeitems = {'printer' : 'Produced by HP', 'paper': 'A4 type', 'drafting pads':
'It is blank', 'scanner': 'it is hybrid', 'table': 'made of wood', 'table lights': 'They
are LED'}

---

for items in officeitems.keys():
print(items.title())
= RESTART: C:/Users/saifia computers/Desktop/sample.py
Printer
Paper
Drafting Pads
Scanner
Table
Table Lights
>>>
Now I will form a loop through each key's values and display the result in the
interpreter.
officeitems = {'printer' : 'Produced by HP', 'paper': 'A4 type', 'drafting pads':
'It is blank', 'scanner': 'it is hybrid', 'table': 'made of wood', 'table lights': 'They
are LED'}
for items in officeitems.values():
print(items.title())
= RESTART: C:/Users/saifia computers/Desktop/sample.py
Produced By Hp
A4 Type
It Is Blank
It Is Hybrid
Made Of Wood
They Are Led
>>>