* Added dict_slice, a slicing tool returning a subset of a given dict

(or other dict-like object).

sugar.py

@@ -1,6 +1,6 @@
 #!/usr/bin/ipython -pylab
 #
-# $Id: sugar.py,v 1.1 2010-01-22 18:46:50 wirawan Exp $
+# $Id: sugar.py,v 1.2 2010-02-08 19:58:44 wirawan Exp $
 #
 # Created: 20100121
 # Wirawan Purwanto
@@ -10,6 +10,7 @@
 # Beware of their caveats!
 #
 #
+import sys
 
 def ifelse(cond, trueval, *args):
   """An alternative to python's own ternary operator, but with multiple
@@ -29,3 +30,25 @@ def ifelse(cond, trueval, *args):
     if i < len(args): return args[i]
 
   return None # Fallback solution: "None"
+
+
+if sys.version_info < (2,4):
+  def sorted(List):
+    rslt = [ L for L in List ] # == L.copy()
+    rslt.sort()
+    return rslt
+else:
+  #print dir(globals())
+  sorted = sorted
+
+#print dir(globals())
+
+def dict_slice(Dict, *keys):
+  """Returns a shallow copy of the subset of a given dict (or an otherwise
+  hashable object) with a given set of keys.
+
+  Example: if d = {'abc': 12, 'def': 7, 'ghi': 32, 'jkl': 98 }
+  then dict_slice(d, 'abc', 'ghi') will yield {'abc': 12, 'ghi': 32 }
+  """
+  return dict([ (k, Dict[k]) for k in keys ])
+