Basic numerical statistics for python lists

stats.py

'''
Basic statistics on a list


The idea of this project is to find the best width for a column in a table
of data.
'''

class Stats():
    def __init__(self, multiplier=1, percent_flag=False, tolerance=0):
        self.mult = multiplier
        self.percent_flag = percent_flag
        self.tolerance = tolerance
    
    def __call__(self, lst):
        self.orig = lst
        
        if not isinstance(lst, list):
            return
        
        if isinstance(lst[0], int): 
            pass
        elif isinstance(lst[0], str): 
            lst = [len(item) for item in lst]
        
        self.lst = lst
        mean = lambda x: float(sum(x))/len(x)
        var = lambda x: mean([(i-mean(x)) ** 2 for i in x])
        stddev = lambda x: var(x) ** .5
        
        self.min = min(lst)
        self.max = max(lst)
        
        self.mean = mean(lst)
        self.stddev = stddev(lst)
        
        self.filter_below = self.mean + self.mult * self.stddev
        
        percent = lambda x,y: float(len(y)-len(x))/len(y)
        self.excluded = filter(lambda x: x > self.filter_below, lst)
        self.percentage = percent(self.excluded, self.lst)

        if self.tolerance + self.filter_below > self.max:
            self.width = self.max
        else:
            self.width = self.filter_below
        return self.width

    def prettyPrint(self):
        print "Width:", self.width
        print "Filter point:", self.filter_below
        print "Mean:", self.mean
        print "Std dev:", self.stddev
        print "Percentage:", self.percentage
        print "Min:", self.min
        print "Max:", self.max
        print "Diff:", self.max - self.filter_below
        print "Excluded:", sorted(self.excluded)
        print "Tolerance", self.tolerance


if __name__ == '__main__':
    import sys
    
    if len(sys.argv) == 1:
        import random
        import string
        a = [''.join([random.choice(string.ascii_uppercase) for x in range(random.randrange(100))]) for i in range(30)]
        print "No args: Randomly selecting 30 strings 1 to 100 characters in length"
        print 
    else:
        try:
            a = [int(i) for i in sys.argv[1:]]
        except ValueError:
            a = sys.argv[1:]
        
    s = Stats(multiplier=1.25, tolerance=5)
    
    width = s(a)
    s.prettyPrint()