Преобразование из строки

str_number = "42"
number = int(str_number)

# Spaces around are ignored
padded = int(" 42 ")

# Not a number: ValueError, not 0
try:
    int("42 apples")
except ValueError as error:
    print(f"{error = }")

print(f"{number = }")
print(f"{padded = }")