Processing Command Line Arguments

Printing the Command Line Arguments

Code:

#!/usr/bin/env python
# file: echo.py

import sys
print sys.argv

Output:

> chmod +x echo.py
> echo.py tuna
['echo.py', 'tuna']
> echo.py tuna fish
['echo.py', 'tuna', 'fish']
> echo.py "tuna fish"
['echo.py', 'tuna fish']
> echo.py
['echo.py']
>

Computing the Hypotenuse of a Right Triangle

Code:

#!/usr/bin/env python
# file: hypotenuse.py

import sys, math

if len(sys.argv) != 3:  # the program name and the two arguments
  # stop the program and print an error message
  sys.exit("Must provide two positive numbers")

# Convert the two arguments from strings into numbers
x = float(sys.argv[1])
y = float(sys.argv[2])

print "Hypotenuse =", math.sqrt(x**2+y**2)

Output:

> hypotenuse.py 5 12
Hypotenuse = 13.0
> 

Python is Strongly Typed

  math.sqrt("16")
  math.sqrt("16a")
  math.sqrt("16a25")
  math.sqrt("sixteen")
  "1" + 2

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