python - Get the count of first field in the list of lists by iterating through for loop -

by iterating through list of lists trying count of first field lists in list , implement if else logic. not sure if possible in iterator.

input :-  [ [1,'a'],[1,'b'],[2,'c'],[-1,'d'],[-1,'d'] ]  output :-  invalid row invalid row valid row  invalid row invalid row  comments :- 

if count more 1 value such rows invalid otherwise rows valid.

from collections import counter  counts = counter() l in mylist:     counts[l[0]] += 1 l in mylist:     if counts[l[0]] > 1:         print("invalid row")     else:         print("valid row")