Concatenate multi value into one record

Question

I joined two tables together and what I like to do is concatenate multi vaule in one records without duplicated value.

Input Table

Table name: TAXLOT_ZONE
TID ZONE
1 A
1 A
1 B
1 C
2 D
2 D
2 E
3 A
3 B
4 C
5 D
Desirable output table looks like;

table name: Taxlot_zone_out
TID ZONE
1 A, B, C
2 D, E
3 A, B
4 C
5 D

There are no such things as "tables" in pure Python. Are you using a database? If so, what kind of interface? SQL? If so, see http://stackoverflow.com/questions/2451026/minimizing-sql-queries-using-join-with-one-to-many-relationship/2451065#2451065 — Max Shawabkeh, Mar 16 '10 at 22:27
I use file geodatabase or dbf format which is created by ESRI, GIS company. I just want to create a new table from this joined table. — user295216, Mar 16 '10 at 22:37

score 1 · Answer 1 · answered Mar 16 '10 at 22:32

Assuming your table is in sorted order and is iterable, you can use itertools.groupby to group rows with the same first element.

l = [(1, 'A'), (1, 'A'), (1, 'B'), (1, 'C'),
     (2, 'D'), (2, 'D'), (2, 'E'),
     (3, 'A'), (3, 'B'),
     (4, 'C'),
     (5, 'D')]

from itertools import groupby
from operator import itemgetter
result = [(taxlot, list(set(v for k,v in g)))
          for taxlot, g in groupby(l, itemgetter(0))]

Result:

[(1, ['A', 'C', 'B']),
 (2, ['E', 'D']),
 (3, ['A', 'B']),
 (4, ['C']),
 (5, ['D'])]

Concatenate multi value into one record

1 Answers1