# [Tutor] Recognizing real numbers

bob gailer bgailer at gmail.com
Wed Feb 22 22:35:44 CET 2012

```On 2/21/2012 10:00 PM, Michael Lewis wrote:
> Hi everyone,
>
> I have some code where I import a file to use a module. That module
> that I import
> takes text and a multiplier, checks for any numbers in that text and
> will then multiply those numbers by the given multiplier. The imported
> module is below. I am getting the text from a file that I have which
> starts out as:
>
> .5 lb. butter
> 1.75 Cups Graham Cracker Crumbs
> 2.0 Cups Powder Sugar
> 1.0 Cups Peanut Butter
> 2.0 Cups Semi-sweet Chocolate Chips
>
> It seems that the .isdigit() function that I use doesn't recognize the
> .5 as a number and therefore doesn't multiply it. How can I get my
> code to recognize numbers such as .5, 1.75 as numbers?
>
Wow - the requirements just changed. Up tilll now we were dealing with
multiplying each digit. Now we have to parse out a string that
represents a number with decimal places! I hope that we don't raise the
oven temperature in the process.

Is it true that the number to multiply is always at the beginning of a
line? If so that makes the job a lot easier.

> Imported module:
>
> def MultiplyText(text, multiplier):
>     '''Recieve a S & int. For digits in S, multiply by multiplier and
> return updated S.'''
>     return ' '.join(str(float(num) * multiplier) if num.isdigit() else
> num for num in text)
>
> Module doing the importing/opening/reading/creating a new file
>
> import Homework5_1 as multiply
>
> def DoubleDigits(file_name):
>     '''Open file/read file/write new file that doubles all int's in the
>     try:
>     except IOError:
>         return 'No such file.'
>     new_file_name = file_name + '2'
>     try:
>         write_file = open(new_file_name, 'w')
>     except IOError:
>         return 'No such file to write to.'
>         new_line = line.split()
>         new_line = ''.join(multiply.MultiplyText(new_line, 2))
>         write_file.write(new_line + '\n')
>     write_file.close()
>
> def main():
>     DoubleDigits(raw_input('What file do you want to open? '))
>
>
> if '__name__' == '__main__':
>     print main()
>
> Output that is written to my file:
>
> Peanut Butter Bars
>
> Ingredients
>
> .5 lb. butter
> 1.75 Cups Graham Cracker Crumbs
> 4.0 Cups Powder Sugar
> 2.0 Cups Peanut Butter
> 4.0 Cups Semi-sweet Chocolate Chips
>
> Melt butter. Add graham cracker crumbs,
> peanut butter and sugar. Mix well and
> pat into sheet pan. Cover with melted
> chocolate. Refrigerate until semi-firm,
> then cut into squares.
>
> --
> Michael J. Lewis
>
>
>
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> To unsubscribe or change subscription options:
> http://mail.python.org/mailman/listinfo/tutor

--
Bob Gailer
919-636-4239
Chapel Hill NC

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/tutor/attachments/20120222/c11590b8/attachment-0001.html>
```