st: RE: parsing degree minute second

[Nick Cox <n.j.cox@durham.ac.uk>]

My principle and practice with string problems is to reach for regex machinery if and only if simpler tools won't suffice. (When that's not true, they can be very helpful.) 

Thus here the elements you want are the first, third, fifth words of -latitude- to be extracted with -word(latitude, 1)- ... 

I infer that all your data are in the Northern Hemisphere but if not then -word(latitude, -1)- extracts "N" or "S". 

Alternatively, for a regex convenience tool, see -moss- (SSC) and 

. moss lat, regex match(([0-9.]+))

(A rolling -moss- gathers all strings....) 

Nick 
n.j.cox@durham.ac.uk 


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Ben Hoen
Sent: 31 January 2012 18:05
To: statalist@hsphsun2.harvard.edu
Subject: st: parsing degree minute second

Hello statalisters,

I am trying to extract portions of a string "latitude" (in degree minute
seconds) so that I can convert it to decimal degrees.  I have not been able
to get the extraction to work; the ".list" returns null sets for all the
latdd* variables.  Can anyone see my error?

clear all
input str20 latitude
"39 - 46 - 21.02  N"
"39 - 44 - 58.66  N"
"118 - 06 - 27.95  N"
end
gen latdd1=regexs(1) if regexm(latitude, "(([0-9]+)[\ - ]([0-9]+)[\ -
]([0-9]+[\.][0-9]+))")
gen latdd2=regexs(2) if regexm(latitude, "(([0-9]+)[\ - ]([0-9]+)[\ -
]([0-9]+[\.][0-9]+))")
gen latdd3=regexs(3) if regexm(latitude, "(([0-9]+)[\ - ]([0-9]+)[\ -
]([0-9]+[\.][0-9]+))")
list

Thank you in advance for any help you can offer.

Ben


Ben Hoen
Principal Research Associate
Lawrence Berkeley National Laboratory
Office: 845-758-1896
Cell: 718-812-7589
bhoen@lbl.gov
http://eetd.lbl.gov/ea/emp/staff/hoen.html



*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/