Error in taking Comulative_Sum with GH-Python

Hi Guys,

I am trying to get Cumulative Sum of multiple values (n) by using GH-Python as we do in excel, which results in a list of (n) values. But unfortunately, it is just calculating the sum of two consecutive values.

Can anyone help me with through this? I have attached both the excel screenshot and GH-Python Files.

Thanks (6.5 KB)

You are only ever adding two consecutive values from the same list in your Python code. You should instead do as you do with your spreadsheet: take the first value from the running total, the second value from the input list. Here an improved version of your script:

import rhinoscriptsyntax as rs

# Naive implementation simulating spreadsheet
# through using two lists. Not very good, since
# you have to juggle two indices into two separate
# lists, one of them is changing on each run
for G_i in range(-1, len(x)-1):
    x_i = G_i+1 
    if G_i==-1: # check for index, to ensure we do what we need to
        pt1 = 0
        pt1 = float(G[G_i])
    pt2 = float(x[x_i])
    sum = pt1+pt2

A better approach is to just use a running total though. That takes a way the need of fiddling around with indices into two separate lists, and it is less code.

import rhinoscriptsyntax as rs

# simple variable holding the sum as we move through the
# input list

for i in range(len(x)): # note no need for adjusted ranges
    pt1 = float(x[i]) # nor having to index into two different lists
    running_total = running_total + pt1

1 Like

Thanks a lot @nathanletwory for your guidance, It worked ! :slight_smile: