Re: Inserting '-' character in front of all numbers in a string


On Mar 30, 2007, at 4:41 PM, Paul McGuire wrote:

On Mar 30, 2:09 pm, Michael Bentley <mich...@xxxxxxxxxxxxxxxxx> wrote:
On Mar 30, 2007, at 10:38 AM, kevinliu23 wrote:





I want to be able to insert a '-' character in front of all numeric
values in a string. I want to insert the '-' character to use in
conjunction with the getopt.getopt() function.

Rigt now, I'm implementing a menu system where users will be able to
select a set of options like "2a 3ab" which corresponds to menu
choices. However, with getopt.getopt(), it'll only return what I want
if I input -2a -3ab as my string. I don't want the user have to insert
a '-' character in front of all their choices, so I was thinking of
accepting the string input first, then adding in the '-' character
myself.

So my qusetion is, how do I change:

"2a 3ab" into "-2a -3ab".

Will the first character always be a digit?

for i in yourstring.split():
if i[0].isdigit():
yourstring = yourstring.replace(i, '-%s' % (i,))

Or are these hex numbers?- Hide quoted text -

- Show quoted text -

Your replace strategy is risky. If:

yourstring = "1ab 2bc 3de 11ab"

it will convert to

-1ab -2bc -3de 1-1ab

True enough! Good catch! How's this?

for i in yourstring.split():
if i[0].isdigit():
yourstring = yourstring.replace(i, '-%s' % (i,), 1)


.

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