Working with Lists & Dictionaries in Python

Working with Lists & Dictionaries in Python

Introduction and working code for List and Dictionary

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Hi, Guys Today we will learn about List and Dictionaries in python.

Python is an interpreted high-level general-purpose programming language. Its design philosophy emphasizes code readability with its use of significant indentation. Its language constructs as well as its object-oriented approach aim to help programmers write clear, logical code for small and large-scale projects.

Lists

List is an mutable data type in python, it is kind of array but supports not only homogenous list of datatypes but mixture too.

In List index of first element starts from 0, list is used to store multiple variable in one variable.

Creating a list

ls = [ "Saurabh", " hashnode", "Python", " datatype"]
print(ls)
Output
['Saurabh', ' hashnode', 'Python', ' datatype']

Accessing the list element

print(ls[2])
Output
'Python'

We can also use negative indexing:

print(ls[-1])
Output
'datatype'

Creating another list

ls=[1,2,3,4,5]

print(ls)
Output
[1, 2, 3, 4, 5]
print(ls[0]) #?-> 1
print(ls[2])
Output
1
3

Use Negative index

print(ls[-1])
Output
5

Len function

print(len(ls))
Output
5

List insert function

ls.insert(1,"python")
print(ls)
ls.insert(3,"kotlin")
print(ls)
Output
[1, 'python', 2, 3, 4, 5]
[1, 'python', 2, 'kotlin', 3, 4, 5] ##after adding kotlin

Append function

ls.append("gorilla")
print(ls)
Output
[1, 'python', 2, 'kotlin', 3, 4, 5, 'gorilla']

Pop operation

ls.pop()
print(ls)
Output
[1, 'python', 2, 'kotlin', 3, 4, 5]

Pop specific

ls.pop(2)
print(ls)
Output
[1, 'python', 'kotlin', 3, 4, 5]

Remove

ls.remove(3)
print(ls)
Output
[1, 'python', 'kotlin',4, 5]

Clear

ls.clear()
print(ls)
Output
[]

Adding lists into one list

lt=["hello","dance","sheeran"] #creating a new list lt
print(lt)
print(ls)
ls=[1,2,3,4] #creating new list ls
newls=[ls,lt] # adding list as item to list
print(newls)
Output
['hello', 'dance', 'sheeran'] #lt
[1,2,3,4]  #ls
[[1, 2, 3, 4], ['hello', 'dance', 'sheeran']] #newls

Dictionary

Dictionary in Python is an unordered collection of data values, used to store data values like a map, which, unlike other Data Types that hold only a single value as an element, Dictionary holds key:value pair. Key-value is provided in the dictionary to make it more optimized.

Creating a dictionary

The key value are separated by colon ":" and two key-value pair are spearted by ","

dt={"name":"taylor","song":"blank space"}

## Print dictionary
print(dt)
Output
{'name': 'taylor', 'song': 'blank space'}

Access single element

access -> square bracket and pass key name

print(dt["name"])
print(dt["song"])
Output
taylor
blank space

Adding values

dt.update({"Age":23})
print(dt)
Output
{'name': 'taylor', 'song': 'blank space', 'Age': 23}

Pop

dt.pop("song")
print(dt)
Output
{'name': 'taylor', 'Age': 23}

Pop last item

dt.popitem()
print(dt)
Output
{'name': 'taylor'}

Clear

dt.clear()
print(dt)
Output
{}

Overwrite value with key

dt={"name":"taylor","song":"blank space"}

dt.update({"name":"Ed sheeran"})
print(dt)
Output
{'name': 'Ed sheeran', 'song': 'blank space'}

Keys and Values printing

#Print keys

print(dt.keys())
Output
dict_keys(['name', 'song'])
print(dt.values())
Output
dict_values(['Ed sheeran', 'blank space'])

Thank You!!!

Pythoneers , lets meet in next Pyblog.

 
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