Karatasi ya Maelezo ya Python
Rejeleo linalotafutika na linaloweza kuchapishwa la Python 3 — sintaksia, miundo ya data, comprehensions, vitendakazi, klasi, mafaili na maktaba ya kawaida. Bila malipo.
Variables & types
10x = 1
Assign a variable (dynamically typed)
x: int = 1
Optional type annotation
a, b = 1, 2
Multiple assignment
type(x)
Get the type of a value
int('42')
Convert a string to an integer
str(42)
Convert a value to a string
isinstance(x, int)
Type check
None
The null/absence value
x = y = 0
Chained assignment
PI: Final = 3.14
Constant hint (typing.Final)
Strings
11f'Hello {name}'
f-string interpolation
len(s)
String length
s.upper()
Convert to upper case
s.strip()
Remove surrounding whitespace
s.split(',')
Split into a list
','.join(items)
Join a list with a separator
s.replace('a', 'b')
Replace substrings
'a' in s
Membership test
s[1:4]
Slice characters 1 to 3
s[::-1]
Reverse a string
s.startswith('a')
Check the prefix
Lists & tuples
10a = [1, 2, 3]
Create a list
a.append(4)
Add an item to the end
a.insert(0, x)
Insert at an index
a.pop()
Remove and return the last item
a[1:3]
Slice a sublist
sorted(a, reverse=True)
Return a sorted copy
a.sort(key=len)
Sort in place by a key
len(a)
Number of items
t = (1, 2)
Immutable tuple
first, *rest = a
Unpack with a star
Dicts & sets
10d = {'k': 'v'}
Create a dictionary
d['k']
Access a value by key
d.get('k', default)
Get with a fallback
d.keys() / d.values()
View keys or values
d.items()
Iterate key/value pairs
{**a, **b}
Merge dictionaries
a | b
Dict/set union operator
del d['k']
Remove a key
s = {1, 2, 3}
Create a set (unique values)
set(a) & set(b)
Set intersection
Comprehensions
8[x * 2 for x in a]
List comprehension
[x for x in a if x > 0]
Filtered comprehension
{x: x**2 for x in a}
Dict comprehension
{x for x in a}
Set comprehension
(x for x in a)
Generator expression (lazy)
[y for row in m for y in row]
Flatten with nested loops
[a if c else b for x in items]
Conditional value in comprehension
sum(x for x in a)
Aggregate a generator
Control flow
9if x > 0:\n ...
Conditional (indentation matters)
elif / else:
Additional branches
a if cond else b
Ternary expression
for x in range(10):
Loop over a range
for i, x in enumerate(a):
Loop with an index
for a, b in zip(x, y):
Loop two iterables together
while cond:
Loop while true
break / continue
Exit or skip an iteration
match x:\n case 1: ...
Structural pattern matching (3.10+)
Functions
8def f(a, b=1): return a + b
Function with a default argument
def f(*args, **kwargs):
Variadic positional + keyword args
f(name='Sam')
Call with a keyword argument
lambda x: x + 1
Anonymous inline function
def f(a: int) -> int:
Type hints for params and return
@decorator
Wrap a function with a decorator
yield value
Produce a value from a generator
global x / nonlocal x
Rebind an outer-scope variable
Classes
9class A(Base):
Class with inheritance
def __init__(self, x):
Constructor / initializer
self.x = x
Instance attribute
def __str__(self):
String representation
@property
Computed read-only attribute
@staticmethod / @classmethod
Static and class methods
super().__init__()
Call the parent initializer
@dataclass
Auto-generate init/repr/eq
isinstance(obj, A)
Check the instance type
Files, errors & modules
9with open('f.txt') as fh:
Open a file (auto-closed)
fh.read() / fh.readlines()
Read file contents
open('f.txt', 'w').write(s)
Write to a file
try:\n ...\nexcept ValueError as e:
Catch a specific exception
raise ValueError('bad')
Raise an exception
finally:
Always-run cleanup block
import os
Import a module
from math import sqrt
Import a specific name
import numpy as np
Import with an alias
Hakuna kipengele kinacholingana na “:q”.
Kuhusu Karatasi ya Maelezo ya Python
Karatasi hii ya kumbukumbu ya Python hubana Python 3 kwenye ukurasa mmoja unaoweza kutafutwa: variables na aina, strings, lists na tuples, dicts na sets, comprehensions, control flow, functions, classes, na files, errors na modules. Kila mstari huonyesha msimbo unaofanya kazi pamoja na maelezo mafupi.
Hutegemea Python ya kimtindo (idiomatic) — f-strings, slicing, list na dict comprehensions, unpacking, default na keyword arguments, context managers na exception handling — jambo linalofanya iwe ukumbusho wa haraka iwe Python ni lugha yako ya kila siku au ile unayorudia mara kwa mara.
Karatasi hii ni bure na inafanya kazi kabisa upande wa mteja. Ichuje papo hapo kutoka kisanduku cha utafutaji, rambaza kwa menyu ya sehemu inayoning'inia, nakili snippet yoyote kwa bofyo moja na chapisha rejea nzima unapotaka iwe karibu na kibodi yako.
Jinsi ya kutumia Karatasi ya Maelezo ya Python
- Pitia sehemu — Variables & types kupitia Comprehensions hadi Files, errors & modules.
- Andika kwenye kisanduku cha utafutaji kuchuja kila snippet papo hapo kwenye karatasi nzima.
- Ruka kwenye sehemu kama Dicts & sets ukitumia orodha ya yaliyomo inayoning'inia.
- Bofya snippet yoyote au ikoni yake ya kunakili kunakili msimbo wa Python.
- Chapisha ukurasa kwa rejea ya Python 3 isiyohitaji mtandao.
Maswali yanayoulizwa mara kwa mara
Python 3. Snippets hutumia mitindo ya sasa kama f-strings, comprehensions, unpacking na context managers, hivyo hufanya kazi kwenye interpreter yoyote ya kisasa ya Python 3.
Sehemu tisa: variables na aina, strings, lists na tuples, dicts na sets, comprehensions, control flow, functions, classes, na files, errors na modules — msingi wa standard library unaotumia kwenye scripts za kila siku.
Nyaraka rasmi ni za kina kabisa; karatasi hii imefanywa kuwa fupi kwa makusudi. Huonyesha umbo la mstari mmoja la kila mfumo (pattern) pamoja na maelezo mafupi ili uweze kutafuta, kunakili na kuendelea kwa sekunde chache.
Ndiyo — bofya snippet au ikoni yake ya kunakili inayotokea mshale unapopita juu na itaenda moja kwa moja kwenye clipboard yako pamoja na uthibitisho wa "Copied!".
Ndiyo, bure kabisa. Hupakia kwenye kivinjari chako, haihitaji akaunti na inaweza kuchapishwa.
Utafutaji maarufu
python cheat sheet
python syntax reference
python list methods
python dictionary methods
python string methods
list comprehension python
python classes example
python file handling
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