Simple exercise

Terry Reedy tjreedy at udel.edu
Thu Mar 10 13:20:46 EST 2016


On 3/10/2016 4:02 AM, Rodrick Brown wrote:
>  From the following input
>
> 9
> BANANA FRIES 12
> POTATO CHIPS 30
> APPLE JUICE 10
> CANDY 5
> APPLE JUICE 10
> CANDY 5
> CANDY 5
> CANDY 5
> POTATO CHIPS 30
>
> I'm expecting the following output
> BANANA FRIES 12
> POTATO CHIPS 60
> APPLE JUICE 20
> CANDY 20
>
> However my code seems be returning incorrect value

Learn to debug.  The incorrect value is the one for candy.  First, 
reduce you input to the candy lines.  Still get wrong answer?  Then 
print the value in od within the loop after each calculation to see when 
and how it goes wrong.

> #!/usr/bin/env python3
>
> import sys
> import re
> from collections import OrderedDict
>
> if __name__ == '__main__':
>
>    od = OrderedDict()
>    recs = int(input())
>
>    for _ in range(recs):
>      file_input = sys.stdin.readline().strip()
>      m = re.search(r"(\w.+)\s+(\d+)", file_input)
>
>      if m:
>        if m.group(1) not in od.keys():
>          od[m.group(1)] = int(m.group(2))
>        else:
>          od[m.group(1)] += int(od.get(m.group(1),0))
>    for k,v in od.items():
>      print(k,v)
>
> What's really going on here?
>
> $ cat groceries.txt | ./groceries.py
> BANANA FRIES 12
> POTATO CHIPS 60
> APPLE JUICE 20
> CANDY 40
>


-- 
Terry Jan Reedy




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