This example shows how to add and delete column-oriented variables in a table. You also can edit tables using the Variables Editor.
Load the sample patients data and create two tables. Create one table, T, with information collected from a patient questionnaire and create another table, T1, with data measured from the patient.
load patients
T = table(Age,Gender,Smoker);
T1 = table(Height,Weight,Systolic,Diastolic);
Display the first five rows of each table.
T(1:5,:) T1(1:5,:)
ans =
Age Gender Smoker
___ ________ ______
38 'Male' true
43 'Male' false
38 'Female' false
40 'Female' false
49 'Female' false
ans =
Height Weight Systolic Diastolic
______ ______ ________ _________
71 176 124 93
69 163 109 77
64 131 125 83
67 133 117 75
64 119 122 80
The table T has 100 rows and 3 variables.
The table T1 has 100 rows and 4 variables.
Add variables to the table, T, by horizontally concatenating it with T1.
T = [T T1];
Display the first five rows of the table, T.
T(1:5,:)
ans =
Age Gender Smoker Height Weight Systolic Diastolic
___ ________ ______ ______ ______ ________ _________
38 'Male' true 71 176 124 93
43 'Male' false 69 163 109 77
38 'Female' false 64 131 125 83
40 'Female' false 67 133 117 75
49 'Female' false 64 119 122 80
The table, T, now has 7 variables and 100 rows.
If the tables that you are horizontally concatenating have row names, horzcat concatenates the tables by matching the row names. Therefore, the tables must use the same row names, but the row order does not matter.
First create a new variable for blood pressure as a horizontal concatenation of the two variables Systolic and Diastolic. Then, delete the variables Systolic and Diastolic by name using dot indexing.
T.BloodPressure = [T.Systolic T.Diastolic]; T.Systolic = []; T.Diastolic = [];
Alternatively, you can also use parentheses with named indexing to delete the variables Systolic and Diastolic at once, T(:,{'Systolic','Diastolic'}) = [];.
Display the first five rows of the table, T.
T(1:5,:)
ans =
Age Gender Smoker Height Weight BloodPressure
___ ________ ______ ______ ______ _____________
38 'Male' true 71 176 124 93
43 'Male' false 69 163 109 77
38 'Female' false 64 131 125 83
40 'Female' false 67 133 117 75
49 'Female' false 64 119 122 80
T now has 6 variables and 100 rows.
Add a new variable, BMI, in the table, T, to contain the body mass index for each patient. BMI is a function of height and weight.
T.BMI = (T.Weight*0.453592)./(T.Height*0.0254).^2;
The operators ./ and .^ in the calculation of BMI indicate element-wise division and exponentiation, respectively.
Display the first five rows of the table, T.
T(1:5,:)
ans =
Age Gender Smoker Height Weight BloodPressure BMI
___ ________ ______ ______ ______ _____________ ______
38 'Male' true 71 176 124 93 24.547
43 'Male' false 69 163 109 77 24.071
38 'Female' false 64 131 125 83 22.486
40 'Female' false 67 133 117 75 20.831
49 'Female' false 64 119 122 80 20.426
T has 100 rows and 7 variables.
Delete the third variable, Smoker, and the sixth variable, BloodPressure, from the table.
T(:,[3,6]) = [];
Display the first five rows of the table, T.
T(1:5,:)
ans =
Age Gender Height Weight BMI
___ ________ ______ ______ ______
38 'Male' 71 176 24.547
43 'Male' 69 163 24.071
38 'Female' 64 131 22.486
40 'Female' 67 133 20.831
49 'Female' 64 119 20.426
T has 100 rows and 5 variables.
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