How could I dynamically call the function with parameters

Question

Let's say I put the function calls into list,

['next_release()', 'last_release("com_disagg")']

Hope to get the equivalent results of following

How could I get it in Python

iterate the array and dynamically call the function with params.

next_release()
last_release("com_disagg")

call head() method for each function

next_release().head()
last_release("com_disagg").head()

add print for each function

print next_release().head()
print last_release("com_disagg").head()

Answer 1

arr = ['next_release()', 'last_release("com_disagg")']
class t(object):
 def head(self):
 print "inside head"
 return "head printed"
def next_release():
 print "nr"
 return t()
def last_release(var):
 print var
 return t()
for i in arr:
 eval(i)
for i in arr:
 print eval(i+".head()")
for i in arr:
 print eval(i).head()

Output:

nr
com_disagg
nr
inside head
head printed
com_disagg
inside head
head printed
nr
inside head
head printed
com_disagg
inside head
head printed

• Alekhya Vemavarapu: You are not calling head ?

Answer 2

Currently you're storing a string representing a function. That's probably not what you want since it'll force you to use eval which is usually bad.

You could get away with a mapping if you have to do it with strings:

mapping = {
 'next_release()': next_release(),
 'last_release("com_disagg")': last_release("com_disagg")
}

And now you can get the result using the mapping (mapping["next_release()"] ...).

There are two better options using actual functions and not strings:

If you want the list to store the functions' results (after calling them):

functions_results = [next_release(), last_release("com_disagg")]
list_of_functions_heads = [x.head() for x in list_of_functions_results]

If you want the list to store a functions' references (notice I closed the function with arguments in a lambda to create a parameter-less function:

functions_references = [next_release, lambda: last_release("com_disagg")]
list_of_functions_heads = [x().head() for x in list_of_functions_results]

Answer 3

You can use clsoure:

arr = ['next_release()', 'last_release("com_disagg")'] 
def next_release(): 
 def head(): 
 return x; 
def last_release(var): 
 def head(): 
 return y; 
for i in arr:
 print i.head()