False |
Represents the Boolean false value. |
flag = False |
Used in logical expressions. |
None |
Represents the absence of a value or a null value. |
result = None |
Often used for default function return values or placeholders. |
True |
Represents the Boolean true value. |
flag = True |
Used in logical expressions. |
and |
Logical AND operator. |
if x > 0 and y > 0: |
Returns True if both operands are true. |
as |
Used to create an alias. |
import pandas as pd |
Commonly used in import statements. |
assert |
Used for debugging by testing a condition. |
assert x > 0, "x must be positive" |
Raises an AssertionError if the condition is false. |
async |
Declares an asynchronous function. |
async def my_coroutine(): |
Used with asynchronous programming. |
await |
Used to wait for the result of an async function call. |
await my_coroutine() |
Only valid inside async functions. |
break |
Terminates a loop prematurely. |
for i in range(10): break |
Immediately exits the nearest enclosing loop. |
class |
Declares a class. |
class MyClass: |
Used for creating user-defined objects. |
continue |
Skips the rest of the loop iteration. |
for i in range(10): continue |
Proceeds to the next iteration of the loop. |
def |
Defines a function. |
def my_function(): |
Used for defining functions. |
del |
Deletes a reference to an object. |
del my_list[0] |
Removes an item or deletes a variable. |
elif |
Conditional statement. |
if x > 0: elif x < 0: |
Used after an if statement, short for “else if”. |
else |
Specifies a block of code to execute if the if condition is false. |
if x > 0: else: |
Part of an if-else or try-except block. |
except |
Catches exceptions in a try block. |
try: except ValueError: |
Handles specific exceptions. |
finally |
Specifies a block of code to execute no matter what. |
try: finally: |
Always runs after try, whether an exception occurred or not. |
for |
Declares a for loop. |
for i in range(10): |
Iterates over a sequence. |
from |
Imports specific parts of a module. |
from math import pi |
Used with import. |
global |
Declares a global variable. |
global x |
Used to modify variables outside the current scope. |
if |
Declares a conditional statement. |
if x > 0: |
Executes a block of code based on a condition. |
import |
Imports a module. |
import os |
Allows you to use external modules and libraries. |
in |
Tests membership in a sequence. |
if x in my_list: |
Also used in for loops for iteration. |
is |
Tests identity (whether two objects are the same). |
if x is y: |
Compares object identities, not values. |
lambda |
Creates an anonymous function. |
lambda x: x * 2 |
Returns a function object without a name. |
nonlocal |
Declares a non-local variable. |
nonlocal x |
Used in nested functions to refer to variables in the enclosing (but non-global) scope. |
not |
Logical NOT operator. |
if not x: |
Returns the inverse of the truth value. |
or |
Logical OR operator. |
if x > 0 or y > 0: |
Returns True if at least one operand is true. |
pass |
A null statement that does nothing. |
if x > 0: pass |
Often used as a placeholder for future code. |
raise |
Raises an exception. |
raise ValueError("Invalid input") |
Used for error handling. |
return |
Exits a function and returns a value. |
return x * 2 |
Used in function definitions. |
try |
Specifies a block of code to test for exceptions. |
try: except: |
Used for error handling. |
while |
Declares a while loop. |
while x > 0: |
Repeats a block of code while a condition is true. |
with |
Simplifies exception handling by automatically managing resources. |
with open('file.txt') as f: |
Often used for file operations. |
yield |
Pauses a generator and returns a value. |
yield x |
Used in generator functions to produce a sequence of values lazily. |