Let say I have a table in python in the following format:
id1 V1 100
id1 V2 200
id1 V3 0
id2 V1 300
id2 V2 400
id2 V3 1
and I want to convert in to this format:
id1 100 200 0
id2 300 400 1
V1, V2 and V3 are variable names and I do not need to keep them. I just need ids and the values of each variable. Number of variables (Vs) is also unknown but the order of variables is always same. I'm looking for a smarter way to convert rather than looping. Is there any built-in function?
There is no other builtin method but you can group using a dict:
from collections import defaultdict
d = defaultdict(list)
s = """id1 V1 100
id1 V2 200
id1 V3 0
id2 V1 30
id2 V2 400
id2 V3 1"""
for a, _, c in map(str.split, s.splitlines()):
d[a].append(c)
print(["{},{}".format(k,",".join(v)) for k,v in d.items()]
['id2,30,400,1', 'id1,100,200,0']
If you want the output aligned nicely, you can do something like this
if you want to maintain order, use an OrderedDict:
from collections import OrderedDict
d = OrderedDict()
s = """id1 V1 100
id1 V2 200
id1 V3 0
id2 V1 30
id2 V2 400
id2 V3 1"""
for a, _, c in map(str.split, s.splitlines()):
d.setdefault(a, []).append(c)
If it is in a file, you can parse it with the csv lib:
import csv
from collections import OrderedDict
d = OrderedDict()
with open("in.txt") as f:
for k, _, v in csv.reader(f, delimiter=" "):
d.setdefault(k, []).append(v)
The OrderedDict output:
OrderedDict([('id1', ['100', '200', '0']), ('id2', ['30', '400', '1'])])
