How to detect missing values in a string cell array
显示 更早的评论
I have a cell array A like the below:
Columns 1 through 4
{'NAME'} {'STNNBR'} {[<missing>]} {'SAMPNO'} .
I tried to find the location of the missing value by doing the below:
B = ismissing(A)
Why is the value of B zero for all of them? Shouldn't the answer be: 0 0 1 0?
Columns 1 through 4
0 0 0 0
What is the correct way to write this code? Thanks.
2 个评论
Walter Roberson
2025-3-9
Ah, but the missing element is not a character vector, so this is not a cell array of character vectors
Stephen23
2025-3-9
"Why is the value of B zero for all of them? Shouldn't the answer be: 0 0 1 0?"
The ISMISSING documentation states that for a cell array of character vector ISMISSING returns TRUE for empty character vectors: "Missing values are defined according to the data type of A ... {''} — cell of character vectors"
Your data do NOT match this requirement.
"What is the correct way to write this code?"
Use a STRING array:
A = ["NAME", "STNNBR", missing, "SAMPNO"]
ismissing(A)
采纳的回答
You are applying ismissing() to a cell array. That is the same thing as calling
[ismissing(A(1)), ismissing(A(2)), ismissing(A(3)), ismissing(A(4))]
A(1), A(2), A(3), A(4) are all cells -- and the cells are not missing.
You should probably be using a string array rather than a cell array,
A = ["NAME", "STNNBR", nan, "SAMPNO"]
ismissing(A)
but if you insist on using a cell array then you should have something more like
B = {'NAME', 'STNNBR', string(nan), 'SAMPNO'};
cellfun(@(X)any(ismissing(X),'all'), B)
3 个评论
Leon
2025-3-9
Image Analyst
2025-3-9
isempty: There is no data here.
ismissing(): There is data here, but some of it is marked as being invalid.
if isempty([]); disp('empty'); else; disp('not empty'); end
if ismissing([]); disp('missing'); else; disp('not missing'); end
C = {'ab', [1 2 missing], [], missing, ["cd", missing, "ef"]}
cellfun(@isempty, C, 'uniform', 0)
cellfun(@ismissing, C, 'uniform', 0)
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Data Type Identification 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
