getlist question

[MRAB]

Victor Subervi wrote:
> On Thu, Dec 24, 2009 at 3:28 PM, MRAB <python at mrabarnett.plus.com 
> <mailto:python at mrabarnett.plus.com>> wrote:
> 
>     Victor Subervi wrote:
> 
>         Hi;
>         I have the following code:
> 
>              try:
>                trueVal = form.getlist(storeColNames[i])
>                colNames.append(storeColNames[i])
>                if len(trueVal) > 1:
>                  trueVal = string.join(trueVal, ',')
> 
> 
>     Unless you're using a very old version of Python, you should be using
>     the string method:
> 
>              trueVal = ','.join(trueVal)
> 
> 
>                  values.append(trueVal)
>                elif len(trueVal) == 1:
>                  print storeColNames[i], trueVal, '<br />'
>                  trueVal = '%s' % trueVal[0]
>                  values.append(trueVal)
>                if len(trueVal) > 0:
>                  sql = '%s="%s"' % (storeColNames[i], trueVal)
>                  sqlUpdate.append(sql)
>              except:
>                raise
> 
>         This works fine except when storeColNames[i] returns no data.
>         Now, if I were dealing with getfirst instead of getlist, I could
>         easily put in a nonsense default data value such as '%$#' and
>         check for that. But how can I do that or something similar (and
>         preferably more elegant) with getlist, which takes only the one
>         name parameter?
> 
>     You just need to check whether len(trueVal) == 0. Simple.
> 
> 
> The problem is that it doesn't see the value at all
> 
>         trueVal = form.getlist(storeColNames[i])
>         test = ','.join(trueVal)
>         if len(test) == 0:
>           trueVal == ''
>  
> It simply doesn't register storeColNames[i] if there is nothing provided 
> from the referring page. Here's a test printout:
> 
[snip]
> You can see from the above part with breaks that "Availability" isn't 
> logged. But it is in the insert statement...without a value, which 
> throws an error. The complete code follows:
> 
[snip]
Try working through the code by hand for that value.