''' Purpose: for a user-specified dataset, dataset
                 a user-specified column label, label
                 a column value, key
             counts the number of rows whose column values equals key
'''

# get a hold of helpful web functions
import url

# specify base web folder for datasets
CSV_REPOSITORY = 'http://www.cs.virginia.edu/~cs1112/datasets/csv/'

# get dataset of interest
reply = input( 'Enter the name of a data set: ' )

name = reply.strip()

link = CSV_REPOSITORY + name

dataset = url.get_dataset( link )

# get label for the column of interest
reply = input( 'Enter column label for the data set: ' )

label = reply.strip()

# get key value for column of interest
reply = input( 'Enter the key: ' )

key = reply.strip()

print()

# identify header and data from the dataset
header = dataset[ 0 ]

table  = dataset[ 1 : ]

# get the index i of the dataset column of interest
i = header.index(label) #finds which entry has the label we want

#print( i )

# get from dataset, a list of values for the column of interest
column_values = [] #accumulation requires an accumulator
for row in table:
    cell_of_interest = row[i]
    column_values.append(cell_of_interest)
    #for each row, we will grab the value at the corresponding location
    #the spot we're grabbing corresponds to the label asked for earlier
    #we then append that value to our accumulator
# count from that list of values, the number of values equalling the key
number = column_values.count(key) # count the number of times our key occurs
# print the total
print(number)