Type Casting Examples
Short, runnable programs that show python casting in action. Read the explanation, press Run, then change the code and try your own ideas. New to the topic? Start with the Python Casting lesson.
1Reading a quantity typed as text
A value read from a form or file is a string, so cast it before using it in a calculation.
quantity_text = "4"
unit_price = 2.5
total = int(quantity_text) * unit_price
print("Total:", total)Expected outputTotal: 10.0
2Float to int: truncate versus round
int() removes the decimals, round() picks the nearest whole number. Choose on purpose.
average = 84.6
print("Truncated:", int(average))
print("Rounded:", round(average))
print("One decimal:", round(average, 1))Expected outputTruncated: 84
Rounded: 85
One decimal: 84.6
3Turning text into a list of digits
list() splits a string into characters and int() converts each digit, handy for checksum-style tasks.
card = "4539"
digits = [int(ch) for ch in card]
print(digits)
print("Digit sum:", sum(digits))Expected output[4, 5, 3, 9]
Digit sum: 21
4Building a dictionary from pairs
dict() accepts a list of pairs, which is what zip() or a parsed file often gives you.
names = ["apples", "pears", "plums"]
stock = [12, 5, 0]
inventory = dict(zip(names, stock))
print(inventory)
print(inventory["pears"])Expected output{'apples': 12, 'pears': 5, 'plums': 0}
5
5Parsing a yes/no answer correctly
bool("no") would be True, so compare the text instead.
answers = ["yes", "No", "YES", "maybe"]
for answer in answers:
accepted = answer.strip().lower() in ("yes", "y", "true")
print(answer, "->", accepted)Expected outputyes -> True
No -> False
YES -> True
maybe -> False
6Hexadecimal colours and characters
int(text, 16) reads base-16 numbers; chr() and ord() convert between characters and their codes.
colour = "ff8800"
red = int(colour[0:2], 16)
green = int(colour[2:4], 16)
blue = int(colour[4:6], 16)
print(red, green, blue)
print(chr(ord("a") + 1))Expected output255 136 0
b
Practise next
Python Casting exercises → Back to the lesson
Python Data Types examplesPython Numbers examplesPython Input and Output examplesPython ValueError examples