Reputation: 1435
So first let me say that I am a novice at Python and functions seem to be out of my comprehension for the moment but where I am having trouble is having 3 functions be able to call each other. Here is my code(yes I know it is terribly wrong but you should see where I am going):
def menu():
count=gearboxes
cost=subtotal
return subtotal
def quantity():
gearboxes=raw_input("How many gearboxes would you like to order? ")
return menu()
def subtotal(cost):
if (gearboxes<=10):
cost=gearboxes*100.0
print cost
elif (gearboxes>10 and gearboxes<20):
cost=(gearboxes-10)*80.0+1000.0
print cost
elif (gearboxes>20):
cost=(gearboxes-20)*70.0+1000.0+800.0
print cost
else:
print "wtf m8"
return menu()
def summary():
print "="*80
print "%60s %20f %20f" % ("motors",count,cost)
print "="*80
print quantity()
print subtotal(menu)
print summary(menu)
There is it and any help would be greatly appreciated if you could explain also kind of how functions call on each other.
Thanks!
fixed version(still working)
def quantity():
motors=raw_input("How many motors would you like to order? ")
gearboxes=raw_input("How many gearboxes would you like to order? ")
sensors=raw_input("How many sensor boards would you like to order? ")
return int(motors),int(gearboxes),int(sensors)
def subtotal(motors,gearboxes,sensors):
if motors<=10 and gearboxes<=15:
motorCost=motors*100
gearboxCost=gearboxes*50
sensorCost=sensors*66
return motorCost, gearboxCost, sensorCost
if motors>10 and motors<=20 and gearboxes>15 and gearboxes<=30:
motorCost=(motors-10)*80+1000
gearboxCost=(gearboxes-15)*40+750
sensorCost=sensors*66
return motorCost, gearboxCost, sensorCost
elif motors>20 and gearboxes>30:
motorCost=(motors-20)*70+1000+800
gearboxCost=(gearboxes-30)*30+750+600
sensorCost=sensors*66
return motorCost, gearboxCost, sensorCost
def summary(motors,gearboxes,sensors,motorCost,gearboxCost,sensorCost):
print "="*80
print "%60s %20d %20d" % ("motors",motors,motorCost)
print "%60s %20d %20d" % ("gearboxes",gearboxes,gearboxCost)
print "%60s %20d %20d" % ("sensor boards",sensors,sensorCost)
print "="*80
def menu():
a,b,c=quantity()
d,e,f=subtotal(a,b,c)
summary(a,b,c,d,e,f)
return
menu()
Upvotes: 2
Views: 638
Reputation: 86260
I made some changes to your code. Treat a function like a question. When you call the function; you're asking the question. What you pass to return
is the answer to the question. So when someone asks for the subtotal
of some number of gearboxes; we return cost
, whatever that may be.
We can then store the return values (the answers) in variables and use them later. For example, to pass to another function. Try to follow how information flows through the program.
def quantity():
count=raw_input("How many gearboxes would you like to order? ")
return int(count)
def subtotal(count):
if count<=10:
cost=count*100.0
return cost
elif count>10 and count<20:
cost=(count-10)*80.0+1000.0
return cost
elif count>20:
cost=(count-20)*70.0+1000.0+800.0
return cost
def summary(count, cost):
print "="*80
print "%60s %20f %20f" % ("motors",count,cost)
print "="*80
def menu():
items = quantity()
sub = subtotal(items)
summary(items, sub)
if __name__ == '__main__':
menu()
Upvotes: 5
Reputation: 642
"subtotal" already calls menu() so I'm not sure what you are asking since you are already calling one function within the other.
Also, I can't see what your program is supposed to do - if your function names would be verbs (print_menu, get_menu, set_menu, throw_menu_on_moon, calculate_subtotal, ...) it would be better to understand for humans.
Also, the names you use (on the right hand side of =) within a function must be known there, so for example
def menu():
count=gearboxes
makes no sense (because "gearboxes" is unknown - on the other hand, "count" is fine since it defines new variable - since it is on the left hand side of =)...
Note that variables are only known within the function you defined them in, so
def f():
gearboxes = 2
def menu():
count=gearboxes
would make no sense either.
But
def f():
return 2
def menu():
gearboxes=f()
count=gearboxes
would make perfect sense.
Read the
def calculate_subtotal(gearbox_count):
as "to calculate subtotal of gearbox count do".
If you then say anywhere outside:
calculate_subtotal(5)
^^^^^^^^^^^^^^^^^^^^^
then the underlined part will be replaced by the result returned.
Otherwise, in Python the lines (in a block) are executed one after another - if you want to do multiple things in sequence, you can just write them one line each, one after another.
"return" is not "goto", "return" gives back the result - and control - to the caller of the function. Then the result is placed into the program "instead of the call".
Upvotes: 0