Need help with some string manip in C#

[kyrathaba]

Maybe someone can help me with this. I'm needing C# code that reliably does the following: given a string of characters, it returns a substring of characters. If the substring has an improperly formatted decimal number, that is the returned substring. Otherwise it returns a zero-length string.

So, as examples, it would detect the following in string "abc3. 04xta": -> returns "3. 04"

And for this string: "3bcd4 0.  25z10": returns "4 0.  25"

What I'm ultimately wanting is for the code to do a string.replace( ) that fixes the misformatting:

"abc3. 04xtra" becomes "abc3.04xtra", and "3bcd4 0.  25z10" becomes "3bcd40.25z10".

I know regular expressions is probably the way to go, but I'm having trouble getting my head around them.

The method I'd like would either return the poorly formatted "decimal number" substring; or, optionally,
it could fix the formatting in that substring and replace all occurrences in the larger string.

The end result is that it would turn this sentence...

"The bread was $3 .49, and it had always been $2 .15 before."

...into the following...

"The bread was $3.49, and it had always been $2.15 before."

[mwb1100]

What constitutes an "an improperly formatted decimal number"?  Is it a decimal number that contains spaces (or whitespace characters)?

What would you want to be returned for the following:

    "abc3.-04xta"

or

    "abc6/. 7?8xta"

[kyrathaba]

For my purposes, an improperly formatted decimal number is any substring which, when any interleaved whitespace or other non-decimal, non alphanumeric characters are removed, forms a decimal number.

"abc3.-04xta" becomes "abc3.04xta"

"abc6/. 7?8xta" becomes "abc6.78xta"

[Renegade]

Does this case present a problem for you? (It is properly formatted.)

The fleet consists of 10 2,000-TEU vessels.

If it does, I think you are in for a world of hurt in deciding how things get resolved.

Also, this case:

The apples were handed out, and John got 10. 5 of them were rotten.

But, just off the cuff, does this pattern work?

([0-9 ]+)\.([0-9 ]+)

[kyrathaba]

That looks workable,  Ren. But any regex would need to capture and replace whitespace before,  among and after the numbers: "9. 07" becomes "9.07", and " 7   6 . 04" becomes "76.04"

[mwb1100]

I think the following algorithm will get you what you want (or close):

  - remove any characters that are not an alpha, a digit, or a decimal point
  - replace runs of alpha characters with a space

Now you have a space-delimited string of the numbers you're looking for.

Some things that might need work or modification:

  - if you want to allow negative numeric values, then you might need to handle the minus sign specially (you discarded it in my question's example, so I figure you're not interested in negative values)
  - if you want to allow a comma to be used as a decimal separator

But I think the basic idea gets you what you're looking for.

[mouser]

I think a regex is the way to go.  Easy to make one that ignores whitespaces, etc.

[Renegade]

That looks workable,  Ren. But any regex would need to capture and replace whitespace before,  among and after the numbers: "9. 07" becomes "9.07", and " 7   6 . 04" becomes "76.04"

-kyrathaba (June 21, 2014, 07:13 PM)

While you can do something like:

( )?([0-9 ]+)\.([0-9 ]+)( )?

You can also concat the capture groups and use string.Trim() or string.Replace(). That's simple and reliable.

[kyrathaba]

Yeah, I installed Regulator, but I really need to do some studying of regexes.

[wraith808]

RegexHero is another you might want to try.  Regexbuddy is the best Regex editor that I've come across.