convert cell array of mixed strings to cell array of numbers

Question

checker 2023-2-8

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1909075-convert-cell-array-of-mixed-strings-to-cell-array-of-numbers

评论： Stephen23 2023-2-9

I have a cell array as follows:

ca = [{' [1000 X X X X]'  }    {' X'             }    {' X'      }    {' 1.234' }];

I would like to convert this into a numeric cell array where 'X' is interperted as 'NaN'. My solution uses the following function:

function out = x2decimal(in)
%sscanf doesn't handle NaN
X = NaN;
out = eval(in);
return

In cellfun:

out = cellfun(@(x) x2decimal(x), ca, 'Uni', false)
out = {1×5 double}    {[NaN]}    {[NaN]}    {[1.2340]}
out{1} = 1000         NaN         NaN         NaN         NaN

My solution works but contains the dreaded eval function. Do you see an alternative that is more mat-thonic?

On windows 10, matlab 2020b.

Thanks,

-Chris

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Dyuman Joshi 2023-2-8

在 MATLAB Online 中打开

Not sure about mat-thonic, but here is another approach -

ca = [{' [1000 X X X X]'  }    {' X'             }    {' X'      }    {' 1.234' }];
ca = replace(ca,'X', 'NaN');
out = cellfun(@str2num, ca, 'uni', 0)
out = 1×4 cell array
    {[1000 NaN NaN NaN NaN]}    {[NaN]}    {[NaN]}    {[1.2340]}

checker 2023-2-9

Thanks, that saves me a custom function. Interestingly, str2num uses eval! I'd use str2double but want to perserve exactly the textual representation of the numbers (which are sourced from a single precision float) and it's not clear to me how str2double would affect the display.

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Answer 1

Stephen23 2023-2-9

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1909075-convert-cell-array-of-mixed-strings-to-cell-array-of-numbers#answer_1167725

编辑：Stephen23 2023-2-9

在 MATLAB Online 中打开

ca = {' [1000 X X X X]', ' X', ' X', ' 1.234' }
ca = 1×4 cell array
    {' [1000 X X X X]'}    {' X'}    {' X'}    {' 1.234'}
out = regexp(ca,'[^\s\[\]]+','match');
out = cellfun(@str2double,out,'uni',0)
out = 1×4 cell array
    {[1000 NaN NaN NaN NaN]}    {[NaN]}    {[NaN]}    {[1.2340]}