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# Re: st: editing string variables to remove letters and keep only numbers

 From Michael McCulloch <[email protected]> To [email protected] Subject Re: st: editing string variables to remove letters and keep only numbers Date Tue, 18 Jun 2013 09:00:26 -0700

```Nick, as it's NOW written (with your correction included), I still receive an "invalid syntax" error.
This is my first exercise in learning -forval-, so even after reviewing the -help- I'm not sure how to troubleshoot further.

forval i = 1/`lmax' {
replace numstr = numstr + substr(id, `i', 1) if
inrange(real(substr(id, `i', 1)), 0, 9)
replace letterstr = letterstr + substr(id, `i', 1) if
!inrange(real(substr(id, `i', 1)), 0, 9)
}

Best wishes,
Michael McCulloch, LAc MPH PhD

--
Pine Street Foundation, since 1989
124 Pine Street | San Anselmo | California | 94960-2674
P: (415) 407-1357 | F: (206) 338-2391 | http://www.PineStreetFoundation.org

On Jun 17, 2013, at 5:09 PM, Nick Cox wrote:

> Should be
>
> forval i = 1/`lmax' {
>
>
> Nick
> [email protected]
>
>
> On 18 June 2013 01:06, Michael McCulloch <[email protected]> wrote:
>> In implementing the example, I wrote, based on the variable "id":
>>
>> gen length = length(id)
>> su length, meanonly
>> local lmax = r(max)
>> gen numstr = ""
>> gen letterstr = ""
>>
>> forval i = 1/`max' {
>>     replace numstr = numstr + substr(id, `i', 1) if
>> inrange(real(substr(id, `i', 1)), 0, 9)
>>     replace letterstr = letterstr + substr(id, `i', 1) if
>> !inrange(real(substr(id, `i', 1)), 0, 9)
>> }
>>
>> The forval statement is where I am getting the invalid syntax error.
>>
>>
>> Best wishes,
>> Michael McCulloch, LAc MPH PhD
>>
>> --
>> Pine Street Foundation, since 1989
>> 124 Pine Street | San Anselmo | California | 94960-2674
>> P: (415) 407-1357 | F: (206) 338-2391 | http://www.PineStreetFoundation.org
>>
>> On Jun 17, 2013, at 5:02 PM, Nick Cox wrote:
>>
>>> Yes. The negation is intended. If a character isn't 0 to 9, it's
>>> regarded as a a letter.
>>>
>>> Show us the exact code you typed to get a better answer.
>>> Nick
>>> [email protected]
>>>
>>>
>>> On 18 June 2013 00:51, Michael McCulloch <[email protected]> wrote:
>>>> Thanks Nick.
>>>>
>>>> On the second inrange argument, does the "!" belong there?
>>>> When I run that forval command, an invalid syntax r(198) code is returned.
>>>>
>>>>
>>>>
>>>> Best wishes,
>>>> Michael McCulloch, LAc MPH PhD
>>>>
>>>> --
>>>> Pine Street Foundation, since 1989
>>>> 124 Pine Street | San Anselmo | California | 94960-2674
>>>> P: (415) 407-1357 | F: (206) 338-2391 | http://www.PineStreetFoundation.org
>>>>
>>>> On Jun 17, 2013, at 4:10 PM, Nick Cox wrote:
>>>>
>>>>> There are is a dedicated functions in -egenmore- (SSC) (-sieve()-)
>>>>> but let's take it from first principles.
>>>>>
>>>>> gen length = length(strvar)
>>>>> su length, meanonly
>>>>> local lmax = r(max)
>>>>>
>>>>> gen numstr = ""
>>>>> gen letterstr = ""
>>>>>
>>>>> forval i = 1/`max' {
>>>>>    replace numstr = numstr + substr(strvar, `i', 1) if
>>>>> inrange(real(substr(strvar, `i', 1)), 0, 9)
>>>>>    replace letterstr = letterstr + substr(strvar, `i', 1) if
>>>>> !inrange(real(substr(strvar, `i', 1)), 0, 9)
>>>>> }
>>>>> Nick
>>>>> [email protected]
>>>>>
>>>>>
>>>>> On 17 June 2013 23:53, Michael McCulloch <[email protected]> wrote:
>>>>>> I have a variable in my dataset that (due to changes in data entry practices over time) contains several styles of the variable ID:
>>>>>>
>>>>>>      - a number (e.g. 164)
>>>>>>      - a letter-number combination (e.g. e64)
>>>>>>      - a comma-separated letter-number combination (e.g. e64,e65)
>>>>>>
>>>>>> In seeking to (A) remove the letters, and (B) separate the comma-separated into two separate variables, ID1 and ID2, I wrote the following argument:
>>>>>>
>>>>>> . split ID, p(",")
>>>>>> . gen str id1_new =""           // make new ID to separate out the "e" from ID
>>>>>> . replace id1_new=substr(id1,2,3)
>>>>>>
>>>>>>
>>>>>> This successfully splits ID into ID1 and ID2.
>>>>>>
>>>>>> This also works if:
>>>>>>      a 3-digit variable has a preceding letter (e64 is changed to 64)
>>>>>>
>>>>>> However, in the case of a 3-digit values WITHOUT PRECEDING LETTER, the first digit is removed (164 is changed to 64).
>>>>>>
>>>>>> Any suggestions would be appreciated.
>>>>>>
>>>>>>
>>>>>> Best wishes,
>>>>>> Michael McCulloch, LAc MPH PhD
>>>>>>
>>>>>> --
>>>>>> Pine Street Foundation, since 1989
>>>>>> 124 Pine Street | San Anselmo | California | 94960-2674
>>>>>> P: (415) 407-1357 | F: (206) 338-2391 | http://www.PineStreetFoundation.org
>>>>>>
>>>>>>
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```