tasks a-s

Task/Named-parameters/Python/named-parameters-1.py

@@ -0,0 +1,5 @@
+def subtract(x, y):
+    return x - y
+
+subtract(5, 3)         # used as positional parameters; evaluates to 2
+subtract(y = 3, x = 5) # used as named parameters;      evaluates to 2

Task/Named-parameters/Python/named-parameters-2.py

@@ -0,0 +1,107 @@
+>>> from __future__ import print_function
+>>>
+>>> def show_args(defparam1, defparam2 = 'default value', *posparam, **keyparam):
+  "Straight-forward function to show its arguments"
+  print ("  Default Parameters:")
+  print ("    defparam1 value is:", defparam1)
+  print ("    defparam2 value is:", defparam2)
+
+  print ("  Positional Arguments:")
+  if posparam:
+    n = 0
+    for p in posparam:
+      print ("    positional argument:", n, "is:", p)
+      n += 1
+  else:
+    print ("    <None>")
+
+  print ("  Keyword Arguments (by sorted key name):")
+  if keyparam:
+    for k,v in sorted(keyparam.items()):
+      print ("    keyword argument:", k, "is:", v)
+  else:
+    print ("    <None>")
+
+
+>>> show_args('POSITIONAL', 'ARGUMENTS')
+  Default Parameters:
+    defparam1 value is: POSITIONAL
+    defparam2 value is: ARGUMENTS
+  Positional Arguments:
+    <None>
+  Keyword Arguments (by sorted key name):
+    <None>
+>>> show_args(defparam2='ARGUMENT', defparam1='KEYWORD')
+  Default Parameters:
+    defparam1 value is: KEYWORD
+    defparam2 value is: ARGUMENT
+  Positional Arguments:
+    <None>
+  Keyword Arguments (by sorted key name):
+    <None>
+>>> show_args( *('SEQUENCE', 'ARGUMENTS') )
+  Default Parameters:
+    defparam1 value is: SEQUENCE
+    defparam2 value is: ARGUMENTS
+  Positional Arguments:
+    <None>
+  Keyword Arguments (by sorted key name):
+    <None>
+>>> show_args( **{'defparam2':'ARGUMENTS', 'defparam1':'MAPPING'} )
+  Default Parameters:
+    defparam1 value is: MAPPING
+    defparam2 value is: ARGUMENTS
+  Positional Arguments:
+    <None>
+  Keyword Arguments (by sorted key name):
+    <None>
+>>> show_args('ONLY DEFINE defparam1 ARGUMENT')
+  Default Parameters:
+    defparam1 value is: ONLY DEFINE defparam1 ARGUMENT
+    defparam2 value is: default value
+  Positional Arguments:
+    <None>
+  Keyword Arguments (by sorted key name):
+    <None>
+>>> show_args('POSITIONAL', 'ARGUMENTS',
+              'EXTRA', 'POSITIONAL', 'ARGUMENTS')
+  Default Parameters:
+    defparam1 value is: POSITIONAL
+    defparam2 value is: ARGUMENTS
+  Positional Arguments:
+    positional argument: 0 is: EXTRA
+    positional argument: 1 is: POSITIONAL
+    positional argument: 2 is: ARGUMENTS
+  Keyword Arguments (by sorted key name):
+    <None>
+>>> show_args('POSITIONAL', 'ARGUMENTS',
+              kwa1='EXTRA', kwa2='KEYWORD', kwa3='ARGUMENTS')
+  Default Parameters:
+    defparam1 value is: POSITIONAL
+    defparam2 value is: ARGUMENTS
+  Positional Arguments:
+    <None>
+  Keyword Arguments (by sorted key name):
+    keyword argument: kwa1 is: EXTRA
+    keyword argument: kwa2 is: KEYWORD
+    keyword argument: kwa3 is: ARGUMENTS
+>>> show_args('POSITIONAL',
+              'ARGUMENTS', 'EXTRA', 'POSITIONAL', 'ARGUMENTS',
+              kwa1='EXTRA', kwa2='KEYWORD', kwa3='ARGUMENTS')
+  Default Parameters:
+    defparam1 value is: POSITIONAL
+    defparam2 value is: ARGUMENTS
+  Positional Arguments:
+    positional argument: 0 is: EXTRA
+    positional argument: 1 is: POSITIONAL
+    positional argument: 2 is: ARGUMENTS
+  Keyword Arguments (by sorted key name):
+    keyword argument: kwa1 is: EXTRA
+    keyword argument: kwa2 is: KEYWORD
+    keyword argument: kwa3 is: ARGUMENTS
+>>> # But note:
+>>> show_args('POSITIONAL', 'ARGUMENTS',
+              kwa1='EXTRA', kwa2='KEYWORD', kwa3='ARGUMENTS',
+              'EXTRA', 'POSITIONAL', 'ARGUMENTS')
+SyntaxError: non-keyword arg after keyword arg
+>>>