A concise, well-organized reference guide covering Python basics, following
official conventions and best practices.
1.RECOMMENDED VS CODE EXTENSIONS
- Python Extension Pack: Bundles essential tools (Python, Django, Jinja support)
- Pylance: Advanced language support, IntelliSense, type checking
- vscode-icons (optional): Visual file-type icons in the explorer
- Sublime Text Keymap (optional): Additional keyboard shortcuts for productivity
2.INSTALL IPYTHON (INTERACTIVE SHELL)
Command:
pip install ipython
Use ipython for interactive coding, debugging, and rapid prototyping.
3.ARITHMETIC OPERATORS
Operator Description Example Result
modulo % : 5%2 = 1
division entiere // : 5//2=2
puissance ** : (3²)² = 3**2*2 = 81
4.STRING OPERATIONS
String literals
text = “Hello”
Concatenation
full = “Hello” + ” ” + “World” # “Hello World”
Repetition (shallow copy)
repeat = “Hi ” * 3 # “Hi Hi Hi “
5.COMPARISON OPERATORS
== Equal to 5 == 5 -> True
!= Not equal to 5 != 3 -> True
>= Greater than or eq 10 >= 5 -> True
<= Less than or eq 3 <= 3 -> True
> Greater than 6 > 5 -> True
<= Less than 5 > 6 -> True
6.VARIABLES & MEMORY MANAGEMENT
a = 25
b = 16
id(a) : Gets memory address (e.g., 140234567890)
id(a)==id(b) false : We can compare
For any value between -5 and 256 characters, python caches the values and therefore the ids will be the same if not different
a=-4 b=-4
id(a)==id(b) true
a=257 b=257
id(a)==id(b) false
7.ASSIGNMENT OPERATIONS
Simple assignment
a = 1
Multiple assignment
a, b, c = 24, 67, 15
Swap values
a, b = b, a
Augmented assignments
a += 10 # a = a + 10
a -= 10 # a = a – 10
a *= 10 # a = a * 10
a /= 2 # a = a / 2 (float result)
a //= 2 # a = a // 2 (floor division)
a **= 2 # a = a ** 2 (exponentiation)
8.VARIABLE NAMING RULES & CONVENTIONS RULES (MANDATORY):
- Use letters, digits, and underscores (_)
- Cannot start with a digit
- Case-sensitive (age != Age)
Style………………Example………………………….Typical Use
……………………………………………………………………………………………………………………………..
snake_case……user_age, total_count……Variables, functions, modules
camelCase…….userName, totalCount…..Less common; used in some APIs
PascalCase…….UserProfile, DataBase…….Class names
BEST PRACTICE: Use snake_case for variables/functions, PascalCase for classes
9.NATIVE DATA TYPES
Type………….. Example………….Description
……………………………………………………………………………………….
int……………… 42, -7………………….Integer numbers
float…………….3.14, -0.5……………Floating-point numbers
str………………..”Hello”, ‘World’….Text strings
bool…………….True, False………..Boolean values
complex……..2+3j……………………Complex numbers
NoneType…..None…………………Represents absence of value
10.TYPE CONVERSION (CASTING)
Check type
type(42) # <class ‘int’>
Convert types
int(“100”) # 100
str(42) # “42”
float(“56.46”) # 56.46
complex(5) # (5+0j)
Boolean conversion
bool(“str”) : Returns true if string is valide
bool(“False”) –> true
Falsy values in Python
These values evaluate to False in boolean context:
bool(False) # False
bool(0) # False
bool(0.0) # False
bool(“”) # False
bool([]) # False
bool({}) # False
bool(None) # False
11.STRING FORMATTING METHODS
name = “John”
surname = “Lys”
age = 14
1. Concatenation (+)
full = surname + ” ” + name –> “Lys John”
2. print() with commas
print(name, surname) –> John Lys
3. Concatenation with casting
print(name + ” ” + surname + ” is ” + str(age) + ” years old”)
4. print() with mixed types
print(name, surname, “is”, age, “years old”)
5. Old-style % formatting
print(“%s %s is %d years old” % (name, surname, age))
6. str.format() – positional
print(“{} {} is {} years old”.format(name, surname, age))
7. str.format() – indexed
print(“{2} {1} is {0} years old”.format(age, surname, name))
8. str.format() – named
print(“{n} {s} is {a} years old”.format(n=name, s=surname, a=age))
9. f-strings (Python 3.6+) – RECOMMENDED
print(f”{name} {surname} is {age} years old”)
BEST PRACTICE: Use f-strings for readability and performance.
12.CONDITIONAL STRUCTURES
if condition
if age >= 19:
…print(“You are an adult!”)
elif 14 < age < 19:
…print(“You are a teenager!”)
elif 5 < age <= 14:
…print(“You are a child!”)
else:
…print(“You are a baby!”)
TIP: Use elif for mutually exclusive branches; keep conditions clear and ordered.
WHILE Loop
name = input(“Enter your name please !”)
loop=true
while loop:
…if name:
……print(f”Hello {nom}, how are you today ?”)
……loop = false
…else:
……nom = input(“Enter your name please !”)
For condifiton
for i in range(10):
…print((i+1)**2)
NOTE: range(n) generates integers from 0 to n-1.
13.SEQUENCES: LISTS & TUPLES
Lists
Can contain any type of data
l=[] # empty list
l=[“Ted”, 34, True, range(15)]
print(l)
print(l[0])
for item in items:
…if isinstance(item, str):
……print(item.upper())
…elif isinstance(item, int):
……print(item ** 2)
…else:
……print(item)
Tuples
Like lists but can’t be modified once created and use ( ) instead of [ ]
data = (“Ted”, 34, True, range(15))
data[0] = “Bob” # ERROR: tuples don’t support item assignment
TIP: Use lists for mutable collections; tuples for fixed, hashable data.
14.FUNCTIONS
def greet(name, age=-1):
…”””Print a greeting message. Age is optional.”””
…print(f”Hello {name}, you are {age} years old!”)
greet(“John”) —–> Hello John, you are -1 years old!
greet(“Anna”, 25) —–> Hello Anna, you are 25 years old!
NOTE: Functions return None by default if no return statement is used.
15.UNPACKING SEQUENCES & DICTIONARIES
List unpacking
names = [“Jean”, “Marie”, “Prune”]
a, b, c = names —–> a=”Jean”, b=”Marie”, c=”Prune”
a, *others = names —–> a=”Jean”, others=[“Marie”, “Prune”]
*others, c = names —–> c=”Prune”, others=[“Jean”, “Marie”]
Dictionary unpacking
data = {“name”: “Jean”, “first”: “Marie”}
print(*data) —–> name first (keys)
print(*data.values()) —–> Jean Marie
print(*data.items()) —–> (‘name’, ‘Jean’) (‘first’, ‘Marie’)
Function argument unpacking
def hello(first, name):
…print(f”Hello {first} {name}”)
Unpack list
args = [“Jean”, “Marie”]
hello(*args) —–> Hello Jean Marie
Unpack dict (keys must match parameter names)
hello(**{“first”: “Marie”, “name”: “Jean”}) —–> Hello Marie Jean
TIP: Use * for positional unpacking, ** for keyword unpacking.
16.LAMBDA (ANONYMOUS) FUNCTIONS
Basic lambda
add = lambda a, b: a + b
add(3, 4) —–> 7
Use in sorting
words = [“Anne”, “Joe”, “Boubacar”]
Sort by length, then alphabetically :
words.sort(key=lambda w: (len(w), w))
print(words) —–> [‘Joe’, ‘Anne’, ‘Boubacar’]
TIP: Lambdas are for short, single-expression functions. Prefer def for complex logic.
17.TERNARY (CONDITIONAL) EXPRESSIONS
def is_adult(age):
…return True if age >= 18 else False
More concise:
def is_adult(age):
…return age >= 18
TIP: Use ternary expressions for simple conditional assignments.
18.VARIABLE-LENGTH ARGUMENTS
*args: arbitrary positional arguments
def total(*args):
…return sum(args)
total(1, 2, 3) —–> 6
**kwargs: arbitrary keyword arguments
def create_profile(**kwargs):
…print(kwargs)
create_profile(name=”Jean”, age=14, role=”DevOps”)
—–> {‘name’: ‘Jean’, ‘age’: 14, ‘role’: ‘DevOps’}
TIP: Use *args for flexible positional inputs; **kwargs for named parameters.
BLOG DBA TIPS AND TRICKS 