## Python 3 Script to Build Grocery List and Calculate Budget and Bill of Items & Products Full Project For Beginners `app.py`

``````# This loop will go on until the budget is integer or float
while True:
try:
bg = float(input("Enter your budget : "))
# if budget is integer or float it will be stored
# temporarily in variable 's'
s = bg
except ValueError:
print("PRINT NUMBER AS A AMOUNT")
continue
else:
break

# dictionary to store product("name"), quantity("quant"),
# price("price") with empty list as their values
a ={"name":[], "quant":[], "price":[]}

# converting dictionary to list for further updation
b = list(a.values())

# variable na value of "name" from dictionary 'a'
na = b

# variable qu value of "quant" from dictionary 'a'
qu = b

# variable pr value of "price" from dictionary 'a'
pr = b

# This loop terminates when user select 2.EXIT option when asked
# in try it will ask user for an option as an integer (1 or 2)
# if correct then proceed else continue asking options
while True:
try:
except ValueError:
print("\nERROR: Choose only digits from the given option")
continue
else:
# check the budget is greater than zero and option selected
# by user is 1 i.e. to add an item
if ch == 1 and s>0:

# input products name
pn = input("Enter product name : ")
# input quantity of product
q = input("Enter quantity : ")
# input price of the product
p = float(input("Enter price of the product : "))

if p>s:
# checks if price is less than budget
print("\nCAN, T BUT THE PRODUCT")
continue

else:
# checks if product name already in list
if pn in na:
# find the index of that product
ind = na.index(pn)

# remove quantity from "quant" index of the product
qu.remove(qu[ind])

# remove price from "price" index of the product
pr.remove(pr[ind])

# insert new value given by user earlier
qu.insert(ind, q)

# insert new value given by user earlier
pr.insert(ind, p)

# subtracting the price from the budget and assign
# it to 's' sum(pr) is because pr = [100, 200] if
# budget is 500 then s = bg-sum(pr) = 200
# after updating for same product at index 0 let
# pr = [200, 200] so s = 100
s = bg-sum(pr)

print("\namount left", s)
else:
# append value of in "name", "quantity", "price"
na.append(pn)

# as na = b it will append all the value in the
# list eg: "name":["rice"]
qu.append(q)

# same for quantity and price
pr.append(p)

# after appending new value the sum in price
# as to be calculated
s = bg-sum(pr)

print("\namount left", s)

# if budget goes zero print "NO BUDGET"
elif s<= 0:
print("\nNO BUDGET")
else:
break

# will print amount left in variable 's'
print("\nAmount left : Rs.", s)

# if the amount left equals to any amount in price list
if s in pr:
# then printing the name of the product which can buy
print("\nAmount left can buy you a", na[pr.index(s)])

print("\n\n\nGROCERY LIST")

# print final grocery list
for i in range(len(na)):
print(na[i], qu[i], pr[i])``````