I've run into a couple of issues using arguments within a python script. Can i please get some help or direction to get this code functional? Thank you in advance.
First issue: I am unable to specify multiple arguments at once. For example I am able to pass a single argument fine:
$ ./my_arg_scenario.py -a
Argument_A
$ ./my_arg_scenario.py -c
Argument_C
$ ./my_arg_scenario.py -d
Argument_D
However, I am looking for a way to pass multiple arguments in any position. Is there a way I can accomplish this? For example, I would like the below to occur:
./my_arg_scenario.py -a -c -d
Argument_A
Argument_C
Argument_D
# OR
./my_arg_scenario.py -c -a
Argument_C
Argument_A
Second Issue: I am trying to pass both whole numbers and floats in the -b argument. But when I pass a float/decimal I get the below error. Is there a way I can pass both a float and whole number?
This works:
$ ./my_arg_scenario.py -b 5
The number provided is: 5
But this does NOT:
$ ./my_arg_scenario.py -b 5.50
Traceback (most recent call last):
File "./my_arg_scenario.py", line 18, in <module>
if int(sys.argv[2]) not in range(0,11):
ValueError: invalid literal for int() with base 10: '5.50'
Below is my testable code:
#!/usr/local/bin/python3.5
import sys
script_options = ['-a', '-b', '-c', '-d']
manual_flag = ''
build_flag = ''
if len(sys.argv) > 1:
if sys.argv[1] in script_options:
pass
else:
print('\n\t\tParameter "' + sys.argv[1] + '" is an invalid argument.\n')
sys.exit()
if sys.argv[1] == '-a':
print('Argument_A')
sys.exit()
elif sys.argv[1] == '-b':
if int(sys.argv[2]) not in range(0,11):
print('Invalid interval. Please select a value bewteen 1-5s.')
sys.exit()
else:
print('The number provided is: ' + (sys.argv[2]))
elif sys.argv[1] == '-c':
manual_flag = 'Argument_C'
print(manual_flag)
elif sys.argv[1] == '-d':
build_flag ='Argument_D'
print(build_flag)
else:
pass
You didn't actually provide the code you're using (aside from incidentally in the traceback), ( Update: Code added later) but the answer is: Stop messing around with parsing sys.argv
manually and use the argparse
module (or docopt
or something that doesn't involve rolling your own switch parsing).
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('-a', action='store_true')
parser.add_argument('-b', metavar='INTERVAL', type=int, choices=range(11))
parser.add_argument('-c', action='store_true')
parser.add_argument('-d', action='store_true')
args = parser.parse_args()
if args.a: print('Argument_A')
if args.b is not None: print('The number provided is:', args.b)
if args.c: print('Argument_C')
if args.d: print('Argument_D')
If you want to accept int
or float
, the easiest solution is to just make type=float
and use a consistent type (but the range
check must be done outside the parsing step). If you must allow both, ast.literal_eval
or a homegrown argparse
type conversion function are options. Since you want a range check too (which range
won't handle properly for float
values that aren't equal to int
values), roll a type checker:
def int_or_float(minval=None, maxval=None):
def checker(val):
try:
val = int(val)
except ValueError:
val = float(val)
if minval is not None and val < minval:
raise argparse.ArgumentTypeError('%r must be >= %r' % (val, minval))
if maxval is not None and val > maxval:
raise argparse.ArgumentTypeError('%r must be <= %r' % (val, maxval))
return val
return checker
Then use it by replacing the definition for -b
with:
# Might want int_or_float(0, 10) depending on range exclusivity rules
parser.add_argument('-b', metavar='INTERVAL', type=int_or_float(0, 11))
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