# reading a number from a string

80 views (last 30 days)
Jim O'Doherty on 17 Jul 2013
Hi all,
I've got a set of strings that are either [1x80] or [1x81], and I'm trying to parse an increasing number from the string. My problem occurs when the length of the string changes due to a number increment. A sample of the strings is:
str='(0020,0013) IS [98] # 2, 1 InstanceNumber'
str='(0020,0013) IS [99] # 2, 1 InstanceNumber'
str='(0020,0013) IS [100] # 2, 1 InstanceNumber'
str='(0020,0013) IS [101] # 2, 1 InstanceNumber'
I'd like to be able to parse the 98, 99, 100, 101 etc from the strings.
The format of the strings is identical, apart from the increasing number.
Currently I can use the following, which fails for the double digit numbers but works for the triple digits:
num=sscanf(str, '%*5c, %*10c %3s')
Any idea how I could make sure I always get the increasing number regardless of its length? It always starts at the same position and is contained in the square brackets.
Cheers, Jim

Azzi Abdelmalek on 17 Jul 2013
str='(0020,0013) IS [98] # 2, 1 InstanceNumber'
pattern='(?<=\[)\d+(?=\])'
out=regexp(str,pattern,'match')
Jim O'Doherty on 18 Jul 2013
3 very good answers which all work perfectly for what I need
Thank you all very much!
Jim

Daniel Pereira on 17 Jul 2013
x = sscanf(str,'(%d,%d) IS [%d] %s %d,%d %s');
num = x([1 2 3 5 6]);
when using
str='(0020,0013) IS [98] # 2, 1 InstanceNumber'
gives
20
13
98
2
1
and when using
str2='(0020,0013) IS [100] # 2, 1 InstanceNumber'
gives
20
13
100
2
1
hope it helps

Image Analyst on 17 Jul 2013
Try this:
index = strfind(str, ']')-1
theNumber = str2double(str(17:index))