Working with Lists & Dictionaries in Python
Introduction and working code for List and Dictionary
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 Specific index
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 values
print(dt.values())
Output
dict_values(['Ed sheeran', 'blank space'])
Thank You!!!
Pythoneers , lets meet in next Pyblog.