Q:

how to generate pie chart using dict_values in Python 3.4? 

I wanted the frequency of numbers in a list which I got using Counter library.  Also, I got the keys and values using keys = Counter(list).keys() and values = Counter(list).values() respectively, where list is the list of numbers.  Their output are in following form:
dict_keys(['0.2200', '0.2700', '0.6200', '0.3000', '0.2500', '0.3400', '0.5600', '0.3900', '0.5400', '0.5500', '0.7500', '0.4100', '0.2800', '0.4200', '0.3800', '0.6600', '0.2000', '0.5200', '0.7200'])

and,
    dict_values([15, 3, 6, 13, 6, 3, 1, 3, 3, 5, 4, 14, 8, 5, 3, 5, 11, 3, 9])
Now I want to generate a pie-chart using keys and values which i did it in following way:
import matplotlib.pyplot as pyplot
pyplot.axis("equal")
pyplot.pie(float(values),labels=float(keys),autopct=None)
pyplot.show()

But, I get the error as:
TypeError: float() argument must be a string or a number, not 'dict_values'

Is there any way to convert dict_values to string or number as the function used to generate pie chart only accepts string or number? 

A:

You need to loop through the values and convert them individually to floats:
pyplot.pie([float(v) for v in values], labels=[float(k) for k in keys],
           autopct=None)

The [expression for target in iterable] is called a list comprehension and produces a list object. 
I'd not create the Counter() twice; create it just once and reuse:
counts = Counter(yourlist)
pyplot.pie([float(v) for v in counts.values()], labels=[float(k) for k in counts],
           autopct=None)

