What am I missing in my initial approach to the code solution for "A Day at the Supermarket"?


#1

This is what I came up with after reading the instructions

"""def revenue(food):
total = 0
sales = prices[key] * stock[key]
for key in prices:
total += prices[x]
return total
print total"""

This is the correct solution I discovered after reading through Q and A

total = 0
for key in prices:
print "price %s" % prices[key]
print "stock %s" % stock[key]
total = prices[key] * stock[key] + total
print key
print total

what am I missing in my initial approach?


#2

@mobanks10gmail.com,

the FUNCTION talk

def myFunc( param1, param2):
    # Begin of =myFunc= FUNCTION-BODY
    # this =myFunc= function- has 2 PARAMETERS param1 and param2
    # param1 and param2 PARAMETERS are used 
    # as -local- VARIABLES throughout the =myFunc= FUNCTION-BODY
    print( param1 + " and " + param2 )
    #End of =myFunc= FUNCTION-BODY

If you want to call/execute the myFunc function
you will have to add a pair of parentheses to myFunc
like
myFunc()
As the myFunc function was defined
as having 2 parameters
you have to provide 2 arguments
in our case 2 string VALUES "Alena" and "Lauren"
like
myFunc("Alena","Lauren")

some quotes from the outer-world:

**argument is the value/variable/reference being passed in,
parameter is the receiving variable used within the function/block**

OR

**"parameters" are called "formal parameters",
while "arguments" are called "actual parameters".**

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++ function with 1 parameter using return-statement

def myFunction( param1 ):
    # //Begin of =myFunction= FUNCTION-BODY
    # //=myFunction= function has 1 PARAMETER param1
    # //this param1 PARAMETER is used as a -local- VARIABLE
    # //throughout the =myFunction= FUNCTION-BODY
    return param1;
    # //End of FUNCTION-BODY

You have defined a myFunction function
which takes 1 parameter param1
this param1 parameter is used
as a variable throughout the =myFunction= FUNCTION-BODY.

If you want to call/execute this myFunction function
and this myFunction function was defined
as having 1 parameter param1
you will have to provide 1 argument
in our case a "number VALUE" 4
myFunction( 4 )

some quotes from the outer-world:

**argument is the value/variable/reference being passed in,
parameter is the receiving variable used within the function/block**

OR

**"parameters" are called "formal parameters",
while "arguments" are called "actual parameters".**

============================================

As you are using the return-statement in your myFunction function
you will only get a return-value no-display.
You can however capture this return-value in a variable
and then use the print-method to do a display.

theResult = myFunction( 4 )
print theResult

OR directly

print myFunction( 4 )

#3

@mobanks10gmail.com,

def revenue(food):
    total = 0
    sales = prices[key] * stock[key]   <--You are using a non-defined VARIABLE =key=
    for key in prices:
        total += prices[x]  <--You are using a non-defined VARIABLE =x=
    return total   <-- =return= returns a VALUE and EXITS the =revenu= function
    print total  <-- this =print= will never be executed as function is already EXITed

#4

Thank you, you have improved my insight to writing functions!