how do I create this loop?

Question

Susan Santiago 2018-10-31

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/427142-how-do-i-create-this-loop

评论： Star Strider 2018-10-31

I have a timetable that I'm converting to an array. Some of the columns are NaNs so initially, I just changed the columns to zeros before converting it but I don't want to do this since not all values in the column are necessarily NaNs and I don't want to lose that possible data. I was thinking of creating a loop so that if the values are NaNs, it'll be changed to a zero and if the value is something else, it'll be left alone. This is what I tried writing for a column called G

 for c = 1:length(TT(:,'G'))
    if TT(c,'G')= nan
        TT(c,'G') = 0;
    else
        TT(c,'G') = TT(c,'G');
end

I know i'm calling the if function wrong but i'm not sure how to fix it. if statements always trip me up for some reason

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Star Strider 2018-10-31

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/427142-how-do-i-create-this-loop#answer_344387

It might be easier to use the timetable2table (link) function, then the table2array (link) function.

I have no idea if this would work with your data. You will have to experiment.

6 个评论
显示 4更早的评论隐藏 4更早的评论

Star Strider 2018-10-31

在 MATLAB Online 中打开

It was something of a challenge for me to figure out how to convert your 'NAN' string entries to numeric NaN values. I am still not certain what you want to do.

This will at least get you started (assuming you already have your ‘TT’ table in your workspace):

TT_T = timetable2table(TT);                                 % Convert To Table
TT_C = table2cell(TT_T);                                    % Convert To Cell
TT_L = cellfun(@(x)strcmpi(x, 'NAN'), TT_C);                % Find 'NAN' Strings
TT_C(TT_L) = {NaN};                                         % Convert String 'NAN' To Numeric {NaN}
TT_M = cell2mat(TT_C(:, 3:end));                            % Data Without ‘datetime’ Objects

The final version of ‘TT_C’ is a cell array with the string 'NAN' elements replaced with numeric NaN elements. The ‘TT_M’ matrix is an array of the data without the first two columns. If you want to include them, use the datenum function to convert them to numeric values. I would not recommend that, although it could be necessary, depending on how you choose to process your data.

Susan Santiago 2018-10-31

This is perfect, thanks so much!

Star Strider 2018-10-31

As always, my pleasure!

请先登录，再进行评论。

Answer 2

Andrei Bobrov 2018-10-31

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/427142-how-do-i-create-this-loop#answer_344386

编辑：Andrei Bobrov 2018-10-31

在 MATLAB Online 中打开

zrs = zeros(size(TT,1),1);
TT.G = zrs;
TT.SG = zrs;

3 个评论
显示 1更早的评论隐藏 1更早的评论

Andrei Bobrov 2018-10-31

I am fixed my answer.

Susan Santiago 2018-10-31

This would just change the whole column to zeros wouldn't it? I explained that that's not what I want to do

请先登录，再进行评论。

how do I create this loop?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

6 个评论
显示 4更早的评论隐藏 4更早的评论

更多回答（1 个）

3 个评论
显示 1更早的评论隐藏 1更早的评论

另请参阅

类别

标签

Community Treasure Hunt

how do I create this loop?

0 个评论 显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

6 个评论 显示 4更早的评论隐藏 4更早的评论

更多回答（1 个）

3 个评论 显示 1更早的评论隐藏 1更早的评论

另请参阅

类别

标签

Community Treasure Hunt

WeChat

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

6 个评论
显示 4更早的评论隐藏 4更早的评论

3 个评论
显示 1更早的评论隐藏 1更早的评论