[Tutor] while loop

[Jay Lozier]

On 03/29/2014 01:18 AM, Scott W Dunning wrote:
> On Mar 28, 2014, at 9:54 PM, Scott W Dunning <scott.w.d at cox.net> wrote:
>
>> Hello, I’m working on some practice exercises from my homework and I’m having some issues figuring out what is wanted.
>>
>> We’re working with the while loop and this is what the question states;
>>
>> Write a function print_n that prints a string n times using iteration.
>>
>> 	"""Print the string `s`, `n` times.
>>
>>
>> This is also in the exercises and I’m not sure what it means and why it’s there.
>>
>> assert isinstance(s, str)
>> assert isinstance(n, int)
>>
>>
>> Any help is greatly appreciated!
>>
>> Scott
> This is what I have so far but I’m not really sure it’s what the excersise is asking for?
>
> n = 5
> def print_n(s, n):
>     while n > 0:
>         print s * n
>
> print_n("hello", 10)
>
Scott,

Are required to use a while loop?

Two ways to solve this, while loop and for in range loop

while loop
n = 5
s = 'some string'

def while_print(s, n):
     index = o
     while index < n:
         print(index, s)
         index += 1

def alternative_print(s, n):
     for index in range(0, n):
         print(index, s)

The while loop requires that a counter variable or some loop exit 
condition so you do not end up in an endless loop. This is a common 
problem with while loops in programming, not just Python. So, if there 
is alternative method of looping available, good programming practice is 
to avoid a while loop in any language. The for loop version 
automatically iterates over the range from 0 to n-1 (5 times). I 
included the index variable in the print to show the increase of the index.

The results for both:
0 some string
1 some string
2 some string
3 some string
4 some string

-- 
Jay Lozier
jslozier at gmail.com