Dictionary And Loops Statement in Python

Dictionary in Python

Dictionaries are used to store data values in key: value pairs, Dictionaries are a fundamental data structure in Python used to store collections of items. Unlike lists or tuples, which are indexed by numerical positions, dictionaries store items in key-value pairs. Keys act as unique identifiers for accessing the corresponding values.

They are unordered, mutable(changeable) & don’t allow duplicate keys.

dict = {

"name": "rahul"

"pet": 10.6

"mark" : [ 83, 94, 96 ]

}

dict[”name”], dict[”pet”], dict[”marks”] “key” : value dict[”key”] = “value” - to assign or add new

 

Dictionary Methods in Python- 

Python dictionaries are powerful collections that store key-value pairs, making them essential for various tasks. Here's a comprehensive overview of commonly used dictionary methods to effectively manage and manipulate data within them.

 

• myDict.keys( )  - returns all keys 
• myDict.values( )  - returns all values 
• myDict.items( )  - returns all (key, val) pairs as tuples 
• myDict.get( “key““ )  - returns the key according to value 
• myDict.update( newDict )  - inserts the specified items to the dictionary

 

Set in Python in Python

Id be glad to provide a comprehensive response on Sets in Python:

Sets in Python

• Sets are unordered, unchangeable collections of unique elements. They are similar to lists in terms of storing elements, but they offer distinct characteristics:
• Uniqueness: Sets cannot contain duplicate elements. If you try to add a duplicate, it will be silently ignored.
• Unordered: Elements in a set are not stored in a specific order. The order you see when printing a set may not be the same when you print it again.
• Mutability: Sets themselves are mutable (you can add or remove elements), but the elements within a set must be immutable (e.g., strings, integers, tuples).

The set is a collection of unordered items. Each element in the set must be unique & immutable. 

nums = { 1, 2, 3, 4 } 

set2 = { 1, 2, 2, 2 } - repeated elements stored only once, so it resolved to {1, 2} 

null_set = set( ) - empty set syntax

 

 

Set Methods in Python -

 

• set.add( el )  - adds an element
• set.remove( el )  - removes the elem an 
• set.clear( )  - empties the set
• set.pop( )  - removes a random value Apna C
• set.union( set2 )  - combines both set values & returns new
• set.intersection( set2 )  - combines common values & returns new new 

 

Loops in Python-

 Loops are fundamental programming constructs that allow you to execute a block of code repeatedly until a certain condition is met.

Loops are used for instructions. Loops are used for sequential traversal. For traversing lists, strings, tuples, etc.

 

1. While loop

Used to execute a block of code as long as a certain condition is True.

 

Syntex -

 

While conditions: 

 

Positive Loop

i = 1

while i <= 10 :

i += 1

print(i)

 

Negative Loop

i = 10

while i >= 1 :

i -= 1

print(i)

 

Infinite Loop

i = 1

while i < 10:

i += 1

print(i)

i = 10

while i > 1:

i -= 1

print(i)

 

2 - For Loops

 Used to iterate over a sequence of items, like lists, tuples, strings, or dictionaries.

Syntax -

for el in list: 

el(element)

list- list=(1,2,3,4)

Example -

List example

1- list=(1, 2, 3, 4)

for el in list:

print(el)

Tuples example

tups ={ 1, 2, 3, 4 }

for el in tups:

print(el)

String example 

str= ("Gopal", "Shyam", "Radhe", "Krishna")

for el in str:

print(el)

Print Character-

 

Str="RAHUL"

for char in str:

print(char)

 

Indexing For loops-

num = [ 23, 43 ,23 , 54 ,75 ,35 ,34, 23]

x=23

idx= 0

for el in num:

if(el == x):

print("found", idx)

print(el)

idx += 1

else:

print("Number Ended")

Use of else -

The else statement is primarily used in two contexts in Python:

str= ("Gopal", "Shyam", "Radhe", "Krishna")

for el in str:

print(el)

else:

print(" String End")

3 -Use Range 

Range functions return a sequence of numbers, starting from 0 by default, and increments by 1 (by default), and stops before a specified number. range( start?, stop, step?)

Syntex

 

range(start?,stop,step?)

for el in range(10):

print(el)

for el in range(1, 6)

print(el)

for el in range(1, 6, 2)

print(el)

Use range odd number -

for el in range(1, 100, 2):

print(el)

Use range even number-

for el in range(2, 100, 2):

print(el)

Statement

Python, a statement is a complete instruction that the Python interpreter can understand and execute. It forms the building block of your Python programs.

 

1. Pass Statement - 

A statement pass is a null statement that does nothing. It is used as a placeholder for future code.

for el in range(10):

pass

print(el)

2 -Break Statement

The break statement in Python is used to prematurely exit a loop (either for or while) when a certain condition is met.

str= "rahul"

for el in str:

if(el == 'u'):

print(" found")

print(el)

print("Char Finding....")

else:

print("Char End")

Use break statement 

str= "rahul"

for el in str:

if(el == 'u'):

print(" U found")

break # (this use break statement)

print(el)

print(" U Finding....")

else:

print("Char End")

Continue Statement -

The continue statement in Python is used to control the flow within a loop (for or while). It instructs the loop to skip the remaining code for the current iteration and immediately jump to the beginning of the next iteration.

 

str= "Bharadwaj"

for el in str:

if(el == 'w'):

print(" W found")

continue  (this use break statement)

print(el)

print("W Finding....")

else:

print("Char End")