'''

grouped_frequency.py

Create a grouped frequency table from a list of numbers

'''

def create_classes(numbers, n):

low = min(numbers)

high = max(numbers)

# width of each class

width = (high - low)/n

classes = []

a = low

b = low + width

classes = []

while a < (high-width):

classes.append((a, b))

a = b

b = a + width

# The last class may be of size

# less than width

classes.append((a, high+1))

return classes

def classify(numbers, classes):

# Create a list with the same number of elements

# as the number of classes

count = [0]*len(classes)

for n in numbers:

for index, c in enumerate(classes):

if n >= c[0] and n < c[1]:

count[index] += 1

break

return count

def read_data(filename):

numbers = []

with open(filename) as f:

for line in f:

numbers.append(float(line))

return numbers

if __name__ == '__main__':

num_classes = int(input('Enter the number of classes: '))

numbers = read_data('marks.txt')

classes = create_classes(numbers, num_classes)

count = classify(numbers, classes)

for c, cnt in zip(classes, count):

print('{0:.2f} - {1:.2f} \t {2}'.format(c[0], c[1], cnt))