比较2D列表的第一个元素并在第二个元素上进行操作

Question

I've a 2D list of numbers in this format:

[['1.1','5000'],['2.1','5003',['3.4','5007'],['3.4','5008'],['8.7','5050'],['21.2','6000'],['21.2','6001'],['99.1','5009']]

I want the output in the format:

1.1 5000
2.1 5003
3.4 5007,5008
8.7 5050
21.2 6000,6001
99.1 5009

The objective is to compare if the same number is coming in the 1st element of a 2D list, if it is same then print its content in the same line using ','

My attempt:

from collections import defaultdict
x=[['1','5000'],['2','5003',['3','5007'],['3','5008'],['8','5050'],['21','6000'],['21','6001'],['99','5009']]
result=defaultdict(list)
for k,v in x:
 result[k].append(v)
result=["{}\t{}\r\n".format(k,",".join(v)) for k,v in result.items()]
print "".join(result)

The problem in my code that it does not come in order. I provided a sorted list but the output is coming in random order. I want to perform operation as it is.

Answer 1

from collections import OrderedDict
x=[['1','5000'],['2','5003'],['3','5007'],['3','5008'],['8','5050'],['21','6000'],['21','6001'],['99','5009']]
result = OrderedDict()
for k,v in x:
    if k in result.keys():
        result[k].append(v)
    else:
        result[k] = [v]
res=["{}\t{}\r\n".format(k,",".join(v)) for k,v in result.items()]
print "".join(res)