How to Find the Average of Particular Numbers in a CSV File

Python - Calculate average for every column in a csv file

Here's a clean up of your function, but it probably doesn't do what you want it to do.
Currently, it is getting the average of all values in all columns:

def average_column (csv):
    f = open(csv,"r")
    average = 0
    Sum = 0
    row_count = 0
    for row in f:
        for column in row.split(','):
            n=float(column)
            Sum += n
        row_count += 1
    average = Sum / len(column)
    f.close()
    return 'The average is:', average

I would use the csv module (which makes csv parsing easier), with a Counter object to manage the column totals and a context manager to open the file (no need for a close()):

import csv
from collections import Counter

def average_column (csv_filepath):
    column_totals = Counter()
    with open(csv_filepath,"rb") as f:
        reader = csv.reader(f)
        row_count = 0.0
        for row in reader:
            for column_idx, column_value in enumerate(row):
                try:
                    n = float(column_value)
                    column_totals[column_idx] += n
                except ValueError:
                    print "Error -- ({}) Column({}) could not be converted to float!".format(column_value, column_idx)                    
            row_count += 1.0            

    # row_count is now 1 too many so decrement it back down
    row_count -= 1.0

    # make sure column index keys are in order
    column_indexes = column_totals.keys()
    column_indexes.sort()

    # calculate per column averages using a list comprehension
    averages = [column_totals[idx]/row_count for idx in column_indexes]
    return averages

calculating Average of each cell across multiple csv

import pandas as pd
df=pd.read_csv("a1.csv")
for i in range(2,21):
       filename="a"+str(i)+".csv"
       df+=pd.read_csv(filename)
df=df/20

This should do the trick..

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