Nested loop syntax in python server pages

I am just trying to write a small web page that can parse some text using a regular expression and return the resulting matches in a table. This is the first I've used python for web development, and I have to say, it looks messy.

My question is why do I only get output for the last match in my data set? I figure it has to be because the nested loops aren't formatted correctly.

Here's the data I provide:

groups is just an id correspoding to the regex group, and it's name to provide the header for the table.

pattern is something like:

(\d+)\s(\S+)\s(\S+)$

and data:

12345 SOME USER
09876 SOMEONE ELSE
54678 ANOTHER USER

My simple page:

<%
import re
pattern = form['pattern']
p = re.compile(pattern)
data = form['data']

matches = p.finditer(data)

lines = form['groups'].split("\n")
groupids ={}
for line in lines:
  key, val = line.split(' ')
  groupids[int(key.strip())] = val.strip()

%>
<html>
<table style="border-width:1px;border-style:solid;width:60%;">
<tr>
<%
for k,v in groupids.iteritems():%>
<th style="width:30px;text-align:center"><%= v %></th>
<%
# end
%>
</tr>
<%
for match in matches:
  #begin
%><tr>
<%
for i in range(1, len(match.groups())+1):
  #begin
%>
  <td style="border-style:solid;border-width:1px;border-spacing:0px;text-align:center;"><%= match.group(i) %></td>
<%
  #end
# end
%>
</tr>

</table>
</html>

Edit

Below is the test I ran

Code:

import re
pattern = "(\d\d\d\d\d)\s(\S+)\s(\S+)"

p = re.compile(pattern)

data = """12345 TESTS USERS
34567 TESTS USERS
56789 TESTS USERS"""

groups = """1 PIN
2 FNAME
3 LNAME"""

matches = p.finditer(data)

lines = groups.split("\n")

print lines
groupids ={}
for line in lines:
  key, val = line.split(' ')
  groupids[int(key.strip())] = val.strip()


for k,v in groupids.iteritems():
  print "%s\t" % v,
print ''

for match in matches:
  for i in range(1, len(match.groups())+1):
    print "%s\t" % match.group(i),
  print ''

Output:

PIN     FNAME   LNAME
12345   TESTS   USERS
34567   TESTS   USERS
56789   TESTS   USERS

Solution

<%
for match in matches:
  #begin
%><tr>
<%
for i in range(1, len(match.groups())+1):
  #begin
%>
  <td style="border-style:solid;border-width:1px;border-spacing:0px;text-align:center;"><%= match.group(i) %></td>
<%
  #end
# end
%>

Yeah, you haven't got a nested loop there. Instead you've got a loop over matches that outputs “<tr>\n”, then a second loop over range(...) that only runs after the first has finished. The second is not inside the first because it isn't indented to say so.

From the doc, I think what you need to be saying is:

<%
for match in matches:
    # begin
%><tr><%
    for group in match.groups():
        # begin
%><td style="border-style:solid;border-width:1px;border-spacing:0px;text-align:center;"><%= group %></td><%
    # end
%></tr><%
# end
%>

But I can only agree with your “messy” comment: if PSP is requiring that you torture the indenting of your HTML to fit the structure of your Python like this, it is really Doing It Wrong and you should look for another, less awful templating syntax. There are many, many templating languages for Python that have a more sensible syntax for control structures. As an example, in the one I use the above would look like:

<px:for item="match" in="matches"><tr>
    <px:for item="group" in="match.groups()">
        <td style="border-style:solid;border-width:1px;border-spacing:0px;text-align:center;">
            <?_ group ?>
        </td>
    </px:for>
</tr></px:for>