Detect NaN from table

2021 5 24
1 个回答
更新时间：2021 5 24
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Hello! I would like your help on my issue.
I have an excel file (see attached) that contains daily pollution data from 2006-2016. For the columns B to H I would like to find NaN values for each column, sum them, and in the end, store all these in a new table.
So far I have done this for column B:
[ii jj] = find(isnan(MoT20062016S1.SO2gm3));
outij = sortrows([ii jj]);
length(outij)
How can I expand outij to include columns C to H?
Thanks in advance!
PS. I'm on R2019a

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回答（1 个）

KSSV
KSSV 2021-5-24

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A = [1 2 NaN 5 NaN] ;
idx = isnan(A) ;
A(idx)

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Daphne PARLIARI
Daphne PARLIARI 2021-5-24
Thank you KSSV.
Your answer could only work for one column. I am interested in assessing all 7 columns (B to H) and store the results in the new table outij.
KSSV
KSSV 2021-5-24
Run a loop for each column.
for i = 2:7
t = T.(i)
end
Daphne PARLIARI
Daphne PARLIARI 2021-5-24
Could you please explain what those 3 lines do?
KSSV
KSSV 2021-5-24
It is a loop, which picks each column of table depedning on the loop index.
Are you looking for nansum? Read about it.
Daphne PARLIARI
Daphne PARLIARI 2021-5-24
Let me explain it this way:
Ideally, I want a table (see outij.xlsx attached) that will contain the 7 columns I want to assess, and each column will have saved the positions where a NaN was detected.
E.g. For SO2, the first NaN was detected at place 201 of the original table, the second NaN at position 202 etc.

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