Iterate over tuple list and dictionary to make calc

Question

New to Python - is there a straightforward way to iterate over a tuple list and make a calculation using a performance threshold (ie, daily sales % over/under budgeted sales)? Please see the info below:

daily_sales = [('A',150000),('B',73000),('C',110000),('D',231000),('E',66000)] 
budgeted_sales = {'A':140000,'B':103000,'C':80000,'D':20000,'E':90000}
performance_threshold = .20

Answer 1

To keep things simple, you can do this in a loop. The first line loops through each tuple pair in daily_sales . For the first pair, item[1] is 150000. It then gets item[0] (ie A) from the dictionary. Note that this will fail if there is no matching item in the dictionary.

for item in daily_sales:
    performance = item[1] / float(budgeted_sales.get(item[0])) - 1
    if performance > 0:
        print "Over {0:.2%}".format(performance)
    else:
        print "Under {0:.2%}".format(performance)

Over 7.14%
Under -29.13%
Over 37.50%
Over 1055.00%
Under -26.67%

Answer 2

I guess what you are looking for is something like this:

for i in daily_sales:
    if i[1] > budgeted_sales['A']:
    //Do something

The important bit here is that tuples are immutable, so you access it by referencing a position (eg i[0]). Dict entries can be accessed by referencing their key (eg myDict['myKey']

I Hope this helps!

Answer 3

Since you are new to Python here is an easy way to do that without too complex syntax:

# For each tuple inside daily_sales
for sale in daily_sales:
  # Use the first element of that tuple as a key and check if it's inside the dictionary budgeted_sales
  if sale[0] in budgeted_sales:
    # Compare the value stored for that key with the second element of the tuple (which contains the other price) and print stuff
    if budgeted_sales[sale[0]] > sale[1]: print('Over')
    else: print('Under')

The check above is optional however it ensures that you don't bluntly access the dictionary with a key that doesn't exists and then try to add a non-existent value with an existent one.

Answer 4

Just because no one mentioned it, you can unpack in the for loop to make the code simpler to understand (including the performance_threshold ):

for day, sales in daily_sales:
    performance =  float(sales) / budgeted_sales[day]
    if performance > 1+performance_threshold:
        print "Over {0:.2%}".format(performance)
    elif performance < 1-performance_threshold:
        print "Under {0:.2%}".format(performance)
    else:
        print "Target {0:.2%}".format(performance)

Output:

Target 107.14%
Under 70.87%
Over 137.50%
Over 1155.00%
Under 73.33%