How to sum and average multiple columns? #1505
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jqnatividad
OpenFoam-User
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Hello, I am new to qsv. I have a file with 40 columns that are duplicate: the following columns I want to:
How can I achieve that with qsv? I apperciate your help. |
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Answered by
jqnatividad
Jan 1, 2024
Replies: 1 comment 4 replies
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Hi @OpenFoam-User , can you provide a short sample file with dummy data? It'll make it easier for me to show you various options to achieve your desired result... |
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4 replies
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@jqnatividad: I have attached a sample file below. |
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Just to clarify that I need the columns average not by rows:
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@jqnatividad : Hi! and happy new year :) Could you please provide some hints on how can I solve that using qsv? Thank you |
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Hi @OpenFoam-User , Happy New Year! 🎆 Here's one solution using First, create a luau script named BEGIN {
-- this is the BEGIN block, which is executed ONCE at the beginning
-- where we typically initialize variables, setup functions
-- and load additional Lua libraries as required
-- set to num of repeating columns, set to 4 as the sample data only had 4
num_col_repeats = 4;
-- use string.format using C format specifiers
-- see https://cplusplus.com/reference/cstdio/printf/
function round_string(number, precision)
local fmtStr = string.format('%%0.%sg',precision)
formatted_number = string.format(fmtStr,number)
return formatted_number
end
}!
-- this is the MAIN script loop, which is executed for EACH row
local sum_x = 0;
local sum_u = 0;
local sum_v = 0;
local sum_w = 0;
for i = 0, num_col_repeats-1, 1
do
base = i * 4;
sum_x = sum_x + col[base+1];
sum_u = sum_u + col[base+2];
sum_v = sum_v + col[base+3];
sum_w = sum_w + col[base+4];
end
-- we use a helper round_string function for formatting purposes
-- local avg_x = round_string(sum_x / num_col_repeats, 5);
-- local avg_u = round_string(sum_u / num_col_repeats, 5);
-- local avg_v = round_string(sum_v / num_col_repeats, 5);
-- local avg_w = round_string(sum_w / num_col_repeats, 5);
-- OR use this version if you don't want to round. We need to do
-- tostring as avg_w is really small and rounds to zero using luau defaults
-- if we don't explicitly convert to string first
local avg_x = tostring(sum_x / num_col_repeats);
local avg_u = tostring(sum_u / num_col_repeats);
local avg_v = tostring(sum_v / num_col_repeats);
local avg_w = tostring(sum_w / num_col_repeats);
-- avg_w will always be zero if we don't round or convert it to string explicitly
-- local avg_w = sum_w / num_col_repeats;
-- qsv_log("info", "avg_x = " .. avg_x .. ", avg_u = " .. avg_u .. ", avg_v = " .. avg_v .. ", avg_w = " .. avg_w );
-- return all the avg values
return {avg_x, avg_u, avg_v, avg_w};Now issue the command:
It will add the to just get the avg columns, add the --remap option:
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Hi @OpenFoam-User ,
Happy New Year! 🎆
Here's one solution using
luau:First, create a luau script named
xuvw_avgs.luauwith the following contents: