Retrieve numbers from a string

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Retrieve numbers from a string

Thordog

Ten Centuries

Points: 1322
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February 16, 2010 at 10:36 am

#220698

Comments posted to this topic are about the item Retrieve numbers from a string
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Remember as you walk down lifes road, don't forget to stop and pee on the bushes - Thordog[/font]

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Thordog Ten Centuries Points: 1322 More actions · Answer 1

I noticed if the number was at the end of a sentence, it would not work. For example 'this is 9.00.', the period would mess it up. So I added a check for that right before the check for more than 1 decimal:

if right(@charnum,1) = '.' begin

set @charnum = left(@charnum,len(@charnum)-1)

end

-- don't convert numbers with more than 1 decimal

if len(replace(@charnum,'.','. ')) - len(@charnum) <= 1

begin

-- convert to float, insert into table

insert into @numbers values (@cnt,convert(float,@charnum))

end

That seemed to fix most of it, but I still have a problem with it now converting the string '9.00.' into 90. I have not had time to work on this again, so if you know a solution, I would be thankful!

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Remember as you walk down lifes road, don't forget to stop and pee on the bushes - Thordog[/font]

nigel. SSChampion Points: 11636 More actions · Answer 2

Was looking at this and thinking there has to be a set-based way to acheive the same thing.

This is what I've come up with so far. Might be useful to read Jeff Modens article on Tally tables first (link in my sig below) if you're not already familiar with it.

I've omitted a few things on purpose so as not to obscure the main details of the query, like casting to decimal and checking for invalid strings with ISNUMERIC.

DECLARE @t TABLE(test varchar(8000))

INSERT @t

SELECT ' 1 iop 2?,.3e[]-4-@135.678;0--0;0...0'

SELECT

N,

number = SUBSTRING(test,N,PATINDEX('%[-.0123456789][^.0123456789]%',SUBSTRING(test+',',N,LEN(test)-N+2)))

FROM

@t, Tally

WHERE

N <= LEN(test) -- Restrict rows to the number of cahracters in the string

AND

CHARINDEX(SUBSTRING(test,N,1),'-.0123456789') > 0 -- Only rows starting with a valid numeric start character

AND

(N=0 OR CHARINDEX(SUBSTRING(test,N-1,1),'-.0123456789') = 0) -- either at the start of the string or following an invalid character.

This is basically an extrapolation of Jeffs string-splitting method.

In some basic tests I've done it's outperformed the looping method by a factor of 7 or 8.

I'm sure there are even faster methods and I've no doubt some of the more experienced posters on this site will be along to show us some CLR or XML method that's way beyond me 🙂

Nigel
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Thordog Ten Centuries Points: 1322 More actions · Answer 3

Thanks Nigel, I got to play with this a little today. I have read Jeff's Tally table article before, good stuff! I knew there had to be a good set based way to do it. I will try and tweak it as I have time.

Thank you again 😀

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Remember as you walk down lifes road, don't forget to stop and pee on the bushes - Thordog[/font]

nigel. SSChampion Points: 11636 More actions · Answer 4

No problem, thanks for the feedback.

Hope other people find it useful too.

Nigel
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akljfhnlaflkj SSC Guru Points: 76202 More actions · Answer 5

akljfhnlaflkj

SSC Guru

Points: 76202

May 12, 2016 at 7:31 am

#1878617

Thanks for the script.