在Python列表中找到最小的数字

Question

I am trying to use a for loop to get an average for each week and for the month in python:

sum = 0
sumA = 0
sumB = 0
sumC = 0
sumD = 0

week1 = (35,38,30,34,27,40,39)
week2 = (35,38,30,34,27,40,39)
week3 = (35,38,30,34,27,40,39)
week4 = (35,38,30,34,27,40,39)

for x in (week1):
    sum = sum + week1[x]
    avg1 = (sum + week1[x]) / 7
for y in (week2):
    sumA = sumA + week2[y]
    avg2 = (sumA + week2[y]) / 7
for z in (week3):
    sumB = sumB + week3[z]
    avg3 = (sumB + week3[z]) / 7
for k in (week4):
    sumC = sumC + week4[k]
    avg4 = (sumC + week4[k]) / 7

sumD = sum + sumA + sumB + sumC
avg = (sum + sumA + sumB + sumC) / 28

that is it but its not correct. can i get some help please

Answer 1

Assuming you are using Python 2.x, the / operator for two integers uses integer divsion, ie the result of the division is rounded down to the next integer. Try it in the interactive interpreter:

>>> 5/3
1

To get the correct floating point division, either use

from __future__ import division

or convert one of the operands to float first

avg = float(sum + sumA + sumB + sumC) / 28

Answer 2

You don't need these loops. Here's a quick example:

>>> week1 = (35,38,30,34,27,40,39)
>>> average1 = sum(week1) / len(week1)
>>> average1
34

As in the comments:

The above example (in Python 2.x) needs one part cast to float if you want 'true' division (eg 34.71).

In Python 3.x the single / division defaults to 'true' division so the above snippet would be correct (although with a different resulting value for average1 ).

Answer 3

There are several problems here. First, for x in lst yields the elements of lst , not the indices. Second, you add in the elements twice, once when updating sum , then again when updating avg . Just compute avg outside the list. Third, divide by a float instead of an int to prevent truncation:

for x in (week1):
    sum = sum + x
avg1 = sum / 7.

Answer 4

list = [....]
avg = sum(list)/float(len(list))

Answer 5

>>> def ave(numbers):
...  return sum(numbers) / len(numbers)
... 
>>> week1 = (35,38,30,34,27,40,39)
>>> week2 = (35,38,30,34,27,40,39)
>>> week3 = (35,38,30,34,27,40,39)
>>> week4 = (35,38,30,34,27,40,39)
>>> ave(week1)
34
>>> ave(week1+week2+week3+week4)
34
>>>

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As others pointed out, use from __future__ import division if you want a non-truncated result