" Python is a high level, interepted programming language that was created by Guido van Rossum in 1991. It is well-known for its simplicity, readbility and versatile. the python is very clean and easy to understand, making it an excellent choice for beginners in programming language."
name = Sujit Tomar print(name) #Sujit Tomar
>>> print ("Sujit")
Sujit
>>> 500 * 2
1000
>>> Programming
Traceback (most recent call last):
File "<python-input-0>", line 1, in <module>
Programming
NameError: name 'Programming' is not defined. Did you mean: 'quit'?
It means not variable define
>>> import os
>>> os.getcwd()
'C:\\Users\\PC\\OneDrive\\Documents\\Python'
>>> import abcfgf
Traceback (most recent call last):
File "<python-input-4>", line 1, in <module>
import abcfgf
ModuleNotFoundError: No module named 'abcfgf'
Remember cdw Means :- Current Working Directory
ModuleNotFoundError: it means when you write wrong name of library or module then show this type error
>>> for s in "Sujit":
... print(s)
...
S
u
j
i
t
>>>
<-------------------------------------------------->
>>> for s in "Sujit"
File "<python-input-6>", line 1
for s in "Sujit"
^
SyntaxError: expected ':'
<-------------------------------------------------->
>>> for s in "Sujit":
... print(s)
...
File "<python-input-0>", line 2
print(s)
^^^^^
IndentationError: expected an indented block after 'for' statement on line 1
>>>
>>>
it means you write wrong syntax in python
First you missed (:) because in for loop it is mandatory and Second you miss space (IndentationError) that is error
>>> import sys
>>> sys.platform()
Traceback (most recent call last):
File "<python-input-3>", line 1, in <module>
sys.platform()
~~~~~~~~~~~~^^
TypeError: 'str' object is not callable
>>>
>>> import sys
>>> sys.platform
'win32'
>>>
TypeError: 'str' object is not callable :- Means it is not a function
"When you import allrady any page to another page then use below syntax for update"
>>> from importlib import reload
>>> reload(page)
| Data Type | Discripition | Type | Example |
|---|---|---|---|
| Integers | Immutable | x= 5, y = 10 | |
| Floting Point Numbers | Immutable | a = 3.14, b = 5.36 | |
| Booliean | Immutable | is_active = True, isCompleted = False | |
| String | Immutable | name = 'Sujit', fname = "bob's" | |
| Tuples | Immutable | cordinates = (10, 20) | |
| Frozen set | Immutable | frozen_set_example = frozenset([1, 2,3]) | |
| Bytes | Immutable | bytes_example = b"Sujit Tomar" | |
| List | Mutable | num = [, 2, 3] | |
| Set | Mutable | num = {1, 2, 3} | |
| Dictionary | Mutable | stu = {"name" = "Sujit", "age" = 22} | |
| Bitearray | Mutable | value = bytearray([65, 66, 67]) | |
| Array | it is contain same type value | Mutable | int_array = arrar.array("i", [1, 2, 3]) |
# this is commentsUse ** for for Exponentiation (Power Calculation):
# Squaring a number square = 5 ** 2 # Output: 25 # Cubing a number cube = 3 ** 3 # Output: 27 # Power of any number result = 2 ** 5 # Output: 32
Swapping Two Variables Without a Temporary Variable:
a = 5 b = 10 # Swap values a, b = b, a print(a) # Output: 10 print(b) # Output: 5
List Comprehension :
# Create a list of squares from 0 to 9 squares = [x ** 2 for x in range(10)] print(squares) # Output: [0, 1, 4, 9, 16, 25, 36, 49, 64, 81] # Filter even numbers from a list even_numbers = [x for x in range(20) if x % 2 == 0] print(even_numbers) # Output: [0, 2, 4, 6, 8, 10, 12, 14, 16, 18]
Unpacking Elements in a List:
numbers = [1, 2, 3, 4] # Unpack into variables a, b, c, d = numbers print(a, b, c, d) # Output: 1 2 3 4 # Unpacking with * a, *b, c = numbers print(a, b, c) # Output: 1 [2, 3] 4
Using enumerate() for Index and Value:
fruits = ['apple', 'banana', 'cherry'] for index, fruit in enumerate(fruits): print(index, fruit) # Output: # 0 apple # 1 banana # 2 cherry
Using zip() for Parallel Iteration:
names = ['Alice', 'Bob', 'Charlie'] scores = [85, 90, 95] for name, score in zip(names, scores): print(f'{name}: {score}') # Output: # Alice: 85 # Bob: 90 # Charlie: 95
Ternary Conditional Expression:
# Conditional assignment x = 10 y = 20 max_value = x if x > y else y print(max_value) # Output: 20
Using set() for Removing Duplicates from a List:
numbers = [1, 2, 2, 3, 4, 4, 5] unique_numbers = list(set(numbers)) print(unique_numbers) # Output: [1, 2, 3, 4, 5]
Reversing a String or List:
# Reverse a string text = "hello" reversed_text = text[::-1] print(reversed_text) # Output: "olleh" # Reverse a list my_list = [1, 2, 3, 4, 5] reversed_list = my_list[::-1] print(reversed_list) # Output: [5, 4, 3, 2, 1]
Reversing a String or List:
# Reverse a string text = "hello" reversed_text = text[::-1] print(reversed_text) # Output: "olleh" # Reverse a list my_list = [1, 2, 3, 4, 5] reversed_list = my_list[::-1] print(reversed_list) # Output: [5, 4, 3, 2, 1]
Using _ in the REPL to Access the Last Result:
>>> 10 + 5 15 >>> _ * 2 30
Chaining Comparison Operators:
# Check if a number is between 10 and 20 x = 15 print(10 < x < 20) # Output: True
Merging Two Dictionaries (Python 3.9+):
dict1 = {'a': 1, 'b': 2} dict2 = {'c': 3, 'd': 4} merged_dict = dict1 | dict2 print(merged_dict) # Output: {'a': 1, 'b': 2, 'c': 3, 'd': 4}
Using any() and all() for Logical Checks:
# Check if any number is positive numbers = [-1, -2, 3, -4] print(any(n > 0 for n in numbers)) # Output: True # Check if all numbers are positive print(all(n > 0 for n in numbers)) # Output: False
Sorting a List of Dictionaries by Key:
students = [ {'name': 'Alice', 'grade': 90}, {'name': 'Bob', 'grade': 85}, {'name': 'Charlie', 'grade': 95} ] # Sort by 'grade' sorted_students = sorted(students, key=lambda student: student['grade']) print(sorted_students) # Output: [{'name': 'Bob', 'grade': 85}, {'name': 'Alice', 'grade': 90}, {'name': 'Charlie', 'grade': 95}]
Using defaultdict to Avoid KeyErrors:
from collections import defaultdict # Create a defaultdict with default type 'int' my_dict = defaultdict(int) my_dict['apple'] += 1 print(my_dict) # Output: defaultdict(<class 'int'>, {'apple': 1})
Combining Multiple Strings:
words = ["Python", "is", "fun"] sentence = " ".join(words) print(sentence) # Output: Python is fun
Lambda Functions:
# A simple lambda function to calculate square square = lambda x: x ** 2 print(square(5)) # Output: 25 # Using lambda with `map` numbers = [1, 2, 3, 4] squares = list(map(lambda x: x ** 2, numbers)) print(squares) # Output: [1, 4, 9, 16]
Using Counter to Count Elements in a List:
from collections import Counter elements = ['a', 'b', 'a', 'c', 'b', 'a'] counter = Counter(elements) print(counter) # Output: Counter({'a': 3, 'b': 2, 'c': 1})
Dictionary Comprehension:
# Example: Create a dictionary of squares squares_dict = {x: x ** 2 for x in range(6)} print(squares_dict) # Output: {0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
Using get() to Access Dictionary Values Safely:
my_dict = {'a': 1, 'b': 2} # Access an existing key print(my_dict.get('a')) # Output: 1 # Access a non-existing key (returns None) print(my_dict.get('c')) # Output: None # Providing a default value print(my_dict.get('c', 0)) # Output: 0
math :
>>> import math
>>> math.pi
3.141592653589793
>>>
Random :
>>> import random
>>> random.random()
0.4596604027751191
>>> random.random()
0.20735437958994385
>>> random.random()
0.39390716757344313
>>> random.random()
0.9018445517995602
>>>
>>> random.choice([1, 2, 3, 4, 5])
3
>>> random.choice([1, 2, 3, 4, 5])
4
>>> random.choice([1, 2, 3, 4, 5])
3
>>>
Range :
>>> squar = [x**2 for x in range(10)]
>>> squar
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
>>> cubeNum = [x**3 for x in range (10)]
>>> cubeNum
[0, 1, 8, 27, 64, 125, 216, 343, 512, 729]
>>>