[templatetag.py]

def total_sum(value):
    value_list = value[:, 1:]
    return [sum(i) for i in zip(*value_list)]

[html]

{% load total_sum from templatetag %}

<tr>
  <td>Monthly Total</td>
  <td>{{ monthly_enroll_list|total_sum }}</td> <!-- Total (Jan) -->
  <td>{{ monthly_enroll_list }}</td> <!-- Total (Feb) -->
  <td>{{ monthly_enroll_list }}</td> <!-- Total (Mar) -->
  <td>{{ monthly_enroll_list }}</td>
  <td>{{ monthly_enroll_list }}</td>
  <td>{{ monthly_enroll_list }}</td>
  <td>{{ monthly_enroll_list }}</td>
  <td>{{ monthly_enroll_list }}</td>
  <td>{{ monthly_enroll_list }}</td>
  <td>{{ monthly_enroll_list }}</td>
  <td>{{ monthly_enroll_list }}</td>
  <td>{{ monthly_enroll_list }}</td>
</tr>

1. The value of the "monthy_enroll_list" variable is as follows.

[['A', 3, 1, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8], ['B', 1, 8, 6, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1], ['C', 0, 1, 1, 5, 0, 0, 0, 0, 0, 0, 0, 0, 2], ['D', 2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]]

2. If I remove the index at the beginning and the end of each list, I get the number of enrolls from January to December. I want to get the total sum per month. The values ​​I want to get are:

['6', '10', '12', '6', '0', '0', '0', '0', '0', '0', '0', '0']

3. But i got the following error:

list indices must be integers or slices, not tuple

Thanks for letting me know how to solve it

CodePudding user response：

The issue is the zip function that you're calling. Taking your function, let's focus on the zip part:

# your current function
def total_sum(value):
    value_list = value[:, 1:]
    return [sum(i) for i in zip(*value_list)]

Let's suppose our value is:

v = [[1,2,3], [4,5,6], [7,8,9]]

If we do:

print(list(zip(*v))

We get:

>>> [(1, 4, 7), (2, 5, 8), (3, 6, 9)]

This isn't something we can call sum on as you would be trying to sum a list of tuples.

So instead of

return [sum(i) for i in zip(*value_list)]

in the last line of function, you could change that to:

total = 0
for inner_list in values_list:
    total  = sum(inner_list)
return total

Your new function would therefore become:

def total_sum(value):
    value_list = value[:, 1:]
    total = 0
    for inner_list in values_list:
        total  = sum(inner_list)
    return total