Casting: changing types

Why you need it

Data often arrives as text, even when it looks like a number. Before doing maths, convert it.

age_text = "14"

print(age_text + "1")       # Text: joins
print(int(age_text) + 1)    # Number: adds

print(float("3.5"))         # Text to decimal
print(int(3.9))             # Drops the decimal, doesn't round
print(str(100) + " marks")  # Number to text
print(round(3.9))           # This one rounds

141
15
3.5
3
100 marks
4

Asking the user: input()

On your own computer, input("Your age? ") waits for someone to type, and always gives you back text. That's why you'll often see int(input(...)). The examples on this site set the value directly, so each one runs with a single click.

Code challenge