Question

Using a tuple I would like to autorun a function passing the rest of the tuple as parameters. It’s easier to understand what i’m trying to do if i show you what i have so far:

def Function1(var1,var2,post=False):
    if post: print "Function One "+str(var1)+str(var2)
    return "FN1"

def Function2(var1,var2,var3,var4,post=False):
    if post: print "Function Two "+str(var1)+str(var2)+str(var3)+str(var4)
    return "FN2"


pattern = ( ('Function1',1,2) , ('Function2',1,2,3,4) )
IDs = []

#the next line is the line i can't get working, i[0] is successfully calling
#but i can't get the tuple to pass (var,var,True)
#instead it passes to the function as ((var,var),True)
for i in pattern: IDs += eval(i[0])(i[1:],True)

print IDs

I want my output to be:

'''
Function One 12
Function Two 1234
["FN1","FN2"]
'''

Answer 1

You need three things:

• The magic star operator to turn the list slice into separate
  arguments.
• Making post a named argument so it doesn’t conflict with
  the magic star.
• Append instead of += to separate the returned
  strings properly.

So:

for i in pattern: 
    IDs.append( eval(i[0])(*i[1:],post=True) )

print IDs

Mandatory eval() Lecture: Experienced Python programmers consider eval() to be a dangerous last resort. You should look up functions by name in the local module’s dictionary instead:

for i in pattern:
    # look up i[0] in the symbol dictionary of the current module
    fun = sys.modules[__name__].__dict__[ i[0] ]
    IDs.append( fun(*i[1:],post=True) )

It’s even cleaner and easier if you can restrict the functions to be executed by name to methods within a class object; you need only reference yourObject.__dict__[ functionName ].