On 4/11/2014 1:13 PM, Andoni Gorostiza wrote:
Hi tutor. I need your help with something I don't understand. In the
tutorial, it mentions an example of a range within a range. I'll keep
it simplified. How exactly does this work? I'll provide a few examples.
>>> for x in range(0,5):
...for n in range(0,5):
... print(x)
>>> for x in range(0,5):
...for n in range(0,5)
... print(n)
This one comes from the tutorial:
>>>for n in range(2, 10):
... for x in range(2, n):
... if n % x == 0:
... print(n, 'equals', x, '*', n//x)
... break
... else:
... # loop fell through without finding a factor
... print(n, 'is a prime number')
...
2 is a prime number
3 is a prime number
4 equals 2 * 2
5 is a prime number
6 equals 2 * 3
7 is a prime number
8 equals 2 * 4
9 equals 3 * 3
Can you explain what is going on?
We could but that will not help you learn. Instead I recommend with
pencil and paper you play computer - "execute" (write) the code one step
at a time and write down what happens. Very simple example:
execute: change:
for x in range(0,2): x == 0
for n in range(0,2): n == 0
print(x) output == 0
next for n n == 1
print(x) output == 0
next for x x == 1
for n in range(0,2): n == 0
print(x) output == 1
keep going - at each step write what executes and what changes or happens
When you run into an operation you don't understand stop and either
- look it up
- ask this list
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