Now we would explore applications
of the Python built-in function, input.
Let us write a little program
that converts kilometres to miles.
1 km is equal to 0.621 miles. Or miles
= km multiplied by 0.621.
Before we continue, how are the
numbers 4 and 4.0 different? To a human, they are both the same, both are
number four. However, to Python, they are two different types of numbers.
4 is an integer (whole number)
whereas 4.0 is called a floating-point or float in Python. Therefore, to
multiply or divide two numbers that are likely to have decimal places you have
to make the conversion to float.
Let us comment put the previous
lines of code before we begin. Then type in
mi
= km * 0.621
We need the user to enter the
value for km to be converted. So we can insert that line first
km
= input(‘Please enter distance in kilometres: ‘)
mi
= km* 0.621
print(mi)
Remember, we would be multiplying
our input with a decimal number, in that case, we need to include float to the
input else we get an error message. So our code now becomes
km
= float(input(‘Please enter distance in kilometres: ‘))
mi
= km* 0.621
print(mi)
Let us run the code and supply 10
as input. We get an output of 6.21 as shown below
We could make the output to
actually, say 6.21 miles by including this in the print line by adding the string
‘miles’. Thus the code now becomes
We could also print the output
using the f’ string method with a placeholder { } when we write the print
statement. Let’s add the line below then run the code again
print(f’{mi}
miles’)
We get the same output as can be
seen below
There are other creative ways of
improving output. For example, we could add the string ’10 km in miles is ‘
before printing the output. We can achieve this using both print options
print(km,’in
miles is’,mi,’miles’)
print(f’{km}
in miles is {mi} miles’)
When we run the code again and input
10 we get the same output from both print options.
You could also print a heading
that says what this program does whenever you run it. You can print that at the
top before taking inputs
print(‘KILOMETRE
TO MILES CONVERTER’)
Now the program looks like this
Congratulation!
You have written a code that
converts kilometres to miles.
We could as well easily change
the code to a mile to kilometres converter or even a kilogram to pounds
converter or vice versa.
This is the end of Part One of
our course. Well done!
We would do a few exercises in
subsequent lessons before proceeding to part Two.
