Python argument parser list of list or tuple of tuples
Question:
I’m trying to use argument parser to parse a 3D coordinate so I can use
--cord 1,2,3 2,4,6 3,6,9
and get
((1,2,3),(2,4,6),(3,6,9))
My attempt is
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--cord', help="Coordinate", dest="cord", type=tuple, nargs=3)
args = parser.parse_args(["--cord","1,2,3","2,4,6","3,6,9"])
vars(args)
{'cord': [('1', ',', '2', ',', '3'),
('2', ',', '4', ',', '6'),
('3', ',', '6', ',', '9')]}
What would the replacement of the comma be?
Answers:
You can add your own type. This also allows for additional validations, for example:
def coords(s):
try:
x, y, z = map(int, s.split(','))
return x, y, z
except:
raise argparse.ArgumentTypeError("Coordinates must be x,y,z")
parser.add_argument('--cord', help="Coordinate", dest="cord", type=coords, nargs=3)
For my problem, I had to have a more general approach, not linked to the number of inputs.
Starting from the great answer by georg, I solved my problem as follows
# additional type
def coords(s):
seps = r'[ ;.]'
try:
situp = []
for si in re.split(seps, s):
situp.append(tuple(map(int, si.split(','))))
return situp
except:
raise argparse.ArgumentTypeError("Coordinates must be given divided by commas and space, dot, or semicolon e.g.: 'x,y k,l,m'")
With this, an input like 1,2 3,4,5
will be turned in a list of tuples like [(1,2), (3,4,5)]
EDIT: It might be that the for loop is not optimal, but I wrote it to avoid the use of nargs
EDIT 2:
-
to have a list of list, one should change
the line situp.append(tuple(map(int, si.split(','))))
with situp.append(list(map(int, si.split(','))))
-
to have a tuple of uples one can just change the return with
return tuple(situp)
I’m trying to use argument parser to parse a 3D coordinate so I can use
--cord 1,2,3 2,4,6 3,6,9
and get
((1,2,3),(2,4,6),(3,6,9))
My attempt is
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--cord', help="Coordinate", dest="cord", type=tuple, nargs=3)
args = parser.parse_args(["--cord","1,2,3","2,4,6","3,6,9"])
vars(args)
{'cord': [('1', ',', '2', ',', '3'),
('2', ',', '4', ',', '6'),
('3', ',', '6', ',', '9')]}
What would the replacement of the comma be?
You can add your own type. This also allows for additional validations, for example:
def coords(s):
try:
x, y, z = map(int, s.split(','))
return x, y, z
except:
raise argparse.ArgumentTypeError("Coordinates must be x,y,z")
parser.add_argument('--cord', help="Coordinate", dest="cord", type=coords, nargs=3)
For my problem, I had to have a more general approach, not linked to the number of inputs.
Starting from the great answer by georg, I solved my problem as follows
# additional type
def coords(s):
seps = r'[ ;.]'
try:
situp = []
for si in re.split(seps, s):
situp.append(tuple(map(int, si.split(','))))
return situp
except:
raise argparse.ArgumentTypeError("Coordinates must be given divided by commas and space, dot, or semicolon e.g.: 'x,y k,l,m'")
With this, an input like 1,2 3,4,5
will be turned in a list of tuples like [(1,2), (3,4,5)]
EDIT: It might be that the for loop is not optimal, but I wrote it to avoid the use of nargs
EDIT 2:
-
to have a list of list, one should change
the line
situp.append(tuple(map(int, si.split(','))))
with
situp.append(list(map(int, si.split(','))))
-
to have a tuple of uples one can just change the return with
return tuple(situp)