add more loncapa check functions (choose, rad2deg, deg2rad)

lms/lib/loncapa/loncapa_check.py

@@ -5,7 +5,9 @@
 # Python functions which duplicate the standard comparison functions available to LON-CAPA problems.
 # Used in translating LON-CAPA problems to i4x problem specification language.
 
+from __future__ import division
 import random
+import math
 
 def lc_random(lower,upper,stepsize):
     '''
@@ -15,3 +17,19 @@ def lc_random(lower,upper,stepsize):
     choices = [lower+x*stepsize for x in range(nstep)]
     return random.choice(choices)
 
+def lc_choose(index,*args):
+    '''
+    return args[index]
+    '''
+    try:
+        return args[int(index)-1]
+    except Exception,err:
+        pass
+    if len(args):
+        return args[0]
+    raise Exception,"loncapa_check.lc_choose error, index=%s, args=%s" % (index,args)
+
+deg2rad = 180.0*math.pi
+rad2deg = math.pi * 180
+
+