Question

I have a python question, but i think any programer would know enough to send me in the right direction.I have found some really good code for sorting data. Here is an example of one i want to use:

from operator import itemgetter, attrgetter

data = [('red', 1,80), ('blue', 1,900), ('red', 2,50), ('blue', 2,300)]

ss=sorted(data, key=itemgetter(0))

print ss

my problem is getting data in this specific format as above because i read my data in from a csv file and i can not type it in like the data is above, because i have data stored on files.
I read my data in to python like this:

reader = csv.reader(open("Meterdata2.csv","rb"));

name=[]; idc=[]; startD=[]; endD=[]; cons=[]; monthdays=[];

for row in reader:

if row[0] != 'IB_id':

name.append(str(row[1])) # name

idc.append(long(row[2])) # idc_acct

startD.append(tcnvrt.str2datetime(row[3]))

endD.append(tcnvrt.str2datetime(row[4]))

cons.append(int(row[6])) # consumption

monthdays.append((tcnvrt.str2datetime(row[4])-tcnvrt.str2datetime(row[3])).days)

IDC=array(idc); Name=array(name); STARTD=array(startD); # these are numpy.ndarray

END_D=array(endD); CONS=array(cons); MONTHDAYS=array(monthdays)

AA=[IDC,Name,STARTD,END_D,MONTHDAYS,CONS]

I want to sort my data by my endD variable wich is an array of dates.

I did find some functions online that i think might do the trick of getting data in the specific form to sort it,but i have not been able to figure it out. I keep writing up these function to apply to my example but i can not get them to work.

here are the function i think might work for this (if i change the variables):

   def __init__(self, name, grade, age):
            self.name = name
            self.grade = grade
            self.age = age
    def __repr__(self):
            return repr((self.name, self.grade, self.age))

can someone please push me in the right direction. Thank you

Answer 1

I think you just want to convert it into a list of tuples, before sorting, right? You can do this by using the zip function:

l = zip(name, idc, startD, ...)
l.sort(key=...)

but I do not understand why you do not sort the rows as they are straight away…

l = []
for name, idc, ... in reader:
    if name != ...:
        continue
    l.append((str(name), int(idc), ..))

sorted(l, key=itemgetter(0))