Python cheat sheet for beginners

print("Hello", name, sep=", ", end="\n")   # show values
name = input("Your name? ")                # always returns text
age = int(input("Age? "))                  # convert to a number
x, y = 5, 9                                # two variables at once
x += 1                                     # same as x = x + 1
# a comment: Python ignores this line

s = "Hello, World"
print(len(s), s[0], s[-1], s[0:5], s[::-1])
print(s.upper(), s.lower(), s.replace("World", "India"))
print(s.split(", "), "-".join(["a", "b"]), "  hi ".strip())
print(s.find("World"), s.count("l"), s.startswith("He"), "lo" in s)
n = 3.14159
print(f"{s} has {len(s)} characters; pi is {n:.2f}")

Output

12 H d Hello dlroW ,olleH
HELLO, WORLD hello, world Hello, India
['Hello', 'World'] a-b hi
7 3 True True
Hello, World has 12 characters; pi is 3.14

marks = 68
if marks >= 75:
    grade = "A"
elif marks >= 50:
    grade = "B"
else:
    grade = "C"
print(grade, "pass" if marks >= 33 else "fail")

Output

B pass

for i in range(3):            # 0 1 2
    print(i, end=" ")
for i in range(2, 11, 4):     # 2 6 10
    print(i, end=" ")
print()
n = 3
while n > 0:
    n -= 1
    if n == 1:
        continue              # skip the rest of this round
    print("n is", n)
for number, name in enumerate(["Asha", "Ravi"], 1):
    print(number, name)

Output

0 1 2 2 6 10 
n is 2
n is 0
1 Asha
2 Ravi

a = [5, 2, 9]
a.append(7)            # add at the end
a.insert(0, 1)         # add at a position
a.remove(2)            # remove by value
last = a.pop()         # remove and return the last
a.sort()               # sort in place
print(a, last, len(a), sum(a), min(a), max(a))
print(sorted(a, reverse=True), a[:2], a[-1], 9 in a, a.index(9))
print([x * 2 for x in a if x > 1])

Output

[1, 5, 9] 7 3 15 1 9
[9, 5, 1] [1, 5] 9 True 2
[10, 18]

point = (3, 5)
x, y = point
print(x, y)
s = {1, 2, 2, 3}
s.add(4)
print(sorted(s), sorted(s & {2, 4, 6}), sorted(s - {1}))

Output

3 5
[1, 2, 3, 4] [2, 4] [2, 3, 4]

d = {"tea": 10, "lassi": 40}
d["samosa"] = 15                 # add or change
print(d["tea"], d.get("milk", 0), "tea" in d, len(d))
for key, value in d.items():
    print(key, value)
del d["tea"]
print(list(d.keys()), list(d.values()))

Output

10 0 True 3
tea 10
lassi 40
samosa 15
['lassi', 'samosa'] [40, 15]

def area(length, width=1):
    """Return the area of a rectangle."""
    return length * width

print(area(4, 5), area(4), area(width=2, length=3))

Output

20 4 6

import math, random, datetime
random.seed(1)
print(math.sqrt(16), math.ceil(2.1), math.pi)
print(random.randint(1, 6), random.choice(["a", "b"]))
print(datetime.date(2026, 11, 12).strftime("%d %B %Y"))

Output

4.0 3 3.141592653589793
2 a
12 November 2026

with open("demo.txt", "w", encoding="utf-8") as f:   # "w" write, "a" append, "r" read
    f.write("line one\nline two\n")
with open("demo.txt", encoding="utf-8") as f:
    for line in f:
        print(line.strip())

Output

line one
line two

try:
    n = int("abc")
except ValueError:
    print("not a number")
else:
    print("ok", n)
finally:
    print("always runs")

Output

not a number
always runs

class Student:
    def __init__(self, name, marks):
        self.name = name
        self.marks = marks

    def passed(self):
        return self.marks >= 33

s = Student("Asha", 78)
print(s.name, s.passed())

Output

Asha True