How to conditionally merge multiple variables in a table

Question

Blue 2021-7-21

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/883299-how-to-conditionally-merge-multiple-variables-in-a-table

回答： Star Strider 2021-7-21

Hi,

In the table t below I would like to merge the variables var_c, var_d and var_e into a single new variable called new_var. For a given row, the highest value of the 3 column should be kept. If 2 or 3 values are equal for a given row then it doesnt matter which one is kept. The desired output is desired_output. How would I do that ?

Thank you,

var_a = [1:10]';
var_b = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'k']';
var_c = [1, 2, 3, 4, NaN, NaN, 7, 80, 9, 10]';
var_d = [1, NaN, NaN, 4, NaN, NaN, 7, 8, 9, 90]';
var_e = [NaN, 2, NaN, 4, NaN, NaN, NaN, NaN, 9, 10]';
t = table(var_a, var_b, var_c, var_d, var_e) 
new_var = [1, 2, 3, 4, NaN, NaN, 7, 80, 9, 90]';
desired_output = table(var_a, var_b, new_var)

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Answer 1

Star Strider 2021-7-21

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/883299-how-to-conditionally-merge-multiple-variables-in-a-table#answer_751335

在 MATLAB Online 中打开

Concatenate them horizontally uising square brackets [], then assign the name to the new variable —

var_a = [1:10]';
var_b = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'k']';
var_c = [1, 2, 3, 4, NaN, NaN, 7, 80, 9, 10]';
var_d = [1, NaN, NaN, 4, NaN, NaN, 7, 8, 9, 90]';
var_e = [NaN, 2, NaN, 4, NaN, NaN, NaN, NaN, 9, 10]';
t = table(var_a, var_b, [var_c, var_d, var_e]) 
t = 10×3 table
    var_a    var_b          Var3       
    _____    _____    _________________

      1        a        1      1    NaN
      2        b        2    NaN      2
      3        c        3    NaN    NaN
      4        d        4      4      4
      5        e      NaN    NaN    NaN
      6        f      NaN    NaN    NaN
      7        g        7      7    NaN
      8        h       80      8    NaN
      9        i        9      9      9
     10        k       10     90     10
t.Properties.VariableNames{3} = 'new_var'
t = 10×3 table
    var_a    var_b         new_var     
    _____    _____    _________________

      1        a        1      1    NaN
      2        b        2    NaN      2
      3        c        3    NaN    NaN
      4        d        4      4      4
      5        e      NaN    NaN    NaN
      6        f      NaN    NaN    NaN
      7        g        7      7    NaN
      8        h       80      8    NaN
      9        i        9      9      9
     10        k       10     90     10