import csv,os,fnmatch

def main(folder,index,query):
    filenames = gen_find('*.csv',folder)    
    files = readcsv(filenames)
    lines = files_cat(files)
    data = makerow(lines)
    spreadsheet = makedict(data,'Title')
    print(standarddev(spreadsheet,query))


def average(dictionary,key):
    total,n=0,0
    for element in dictionary:
        try:
            total += float(dictionary[element][key])
            n+=1
        except:
            pass
    return total/(n+1)

def standarddev(dictionary,key):
    a = average(dictionary,key)
    total,n=0,0
    for element in dictionary:
        try:
            total += (a-float(dictionary[element][key]))**2
            n+=1
        except:
            pass
    return a,total/n,(total/n)**0.5
            
def makedict(generator,index):
    d = {}
    for element in generator:
        d[element[index]]=element
    return d
    

def files_cat(generator):
    for file in generator:
        try:
            for line in file:
                yield line
        except:
            pass

def makerow(lines):
    header = next(lines)
    for line in lines:
        if line !=header:
            yield dict(zip(header,line))
          
        
def readcsv(filenames):
    for file in filenames:
        csvfile = open(file,newline='')
        dialect = csv.Sniffer().sniff(csvfile.read(1024))
        csvfile.seek(0)
        reader = csv.reader(csvfile,dialect)
        yield reader
        
def gen_find(filepat,top):
    for path, dirlist, filelist in os.walk(top):
        for name in fnmatch.filter(filelist,filepat):
            yield os.path.join(path,name)

def trace(source):
    for item in source:
        pp.pprint(item)
        yield item 

main()