Operation Manual

Experiments in Python
80
Notes:
Just add Raspberry Pi
So, the same question. What are the factors of all the numbers from 1 to 50? Before
you can start programming, you will need to start up an editor so that you can type
in instructions to the Raspberry Pi.
Open up the IDLE editor as before, but this time use the File menu to select a new
editing window. This is no longer the Python shell, but a text editor. You can type
in your program but it won’t be interpreted by your Raspberry Pi until you tell it to
“Run”. This text editor has been tweaked to make it very good for writing Python,
just as a word processor has been tweaked to check your spelling and grammar.
In this window, type exactly what you see here, including the correct spaces
before each line and all in lowercase. You can use Tab to indent your lines in the
IDLE editor, and it will convert these to spaces.
for number in range( 1, 51):
print(number, ":", end=" ")
for divisor in range(1, number+1):
if number%divisor == 0:
print(divisor, end=" ")
print()
This program uses two loops, “range”, “print”, “if”, “%” and “==”, and two variables
to hold data. The “range” function will generate the numbers from the first to one
below the last; in this case, 1 to 50. The “%” operator will give the remainder after
dividing the two variables.
Also, notice how “==” is used rather than just “=”. This is because, on a computer,
setting a variable to a number is different to comparing the equality of numbers.
Using “==” makes it clear that you want to compare the numbers for equality.
The print function normally ends the line with a carriage return (the same as when you
pressed the Return key). To stop this, you can tell the print function what you want at
the end. In this program, we are telling “print” to put a space character at the end of
the line instead. “print()” will end the line to give us a new row for the next answer.
Tip...
The indent of four
spaces should
appear
automatically
after the line
ending with a
colon (:). The
indent of eight
spaces will
appear after the
second line
ending with a
colon.
Tip...
In computer
maths, the
following symbols
are used rather
than what you
might be used to:
* for multiply,
instead of x
/ for divide,
instead of ÷
% for modulo,
instead of / or
mod.
Open a new editing window
from the File menu in IDLE.
This will allow you to work
in the IDLE text editor.