# Modify Units, Descriptions, and Table Variable Names

This example shows how to access and modify table properties for variable units, descriptions, and names. You also can edit these property values using the Variables Editor.

Load the sample patients data and create a table. `T.LastName` is a cell array of character vectors, so convert to a string array. The table `T` 100 rows and 6 variables. The sixth variable, `BloodPressure`, is a 100-by-2 numeric array.

```load patients BloodPressure = [Systolic Diastolic]; T = table(LastName,Age,Height,Weight,Smoker,BloodPressure); T.LastName = string(T.LastName)```
```T=100×6 table LastName Age Height Weight Smoker BloodPressure __________ ___ ______ ______ ______ _____________ "Smith" 38 71 176 true 124 93 "Johnson" 43 69 163 false 109 77 "Williams" 38 64 131 false 125 83 "Jones" 40 67 133 false 117 75 "Brown" 49 64 119 false 122 80 "Davis" 46 68 142 false 121 70 "Miller" 33 64 142 true 130 88 "Wilson" 40 68 180 false 115 82 "Moore" 28 68 183 false 115 78 "Taylor" 31 66 132 false 118 86 "Anderson" 45 68 128 false 114 77 "Thomas" 42 66 137 false 115 68 "Jackson" 25 71 174 false 127 74 "White" 39 72 202 true 130 95 "Harris" 36 65 129 false 114 79 "Martin" 48 71 181 true 130 92 ⋮ ```

Specify units for each variable in the table by modifying the table property, `VariableUnits`. While the property is a cell array of character vectors, you can assign values to it using a string array.

`T.Properties.VariableUnits = ["","Yrs","In","Lbs","","mm Hg"];`

An individual empty string within the string array indicates that the corresponding variable does not have units.

### Add a Variable Description for a Single Variable

Add a variable description for the variable, `BloodPressure`. Assign text to the element of `VariableDescriptions` that contains the description for `BloodPressure`.

`T.Properties.VariableDescriptions("BloodPressure") = "Systolic/Diastolic";`

You can use the variable name, `BloodPressure`, or the numeric index of the variable, `6`, to index into `VariableDescriptions`.

### Summarize the Table

View the data type, description, units, and other descriptive statistics for each variable by using `summary` to summarize the table.

`summary(T)`
```Variables: LastName: 100x1 string Age: 100x1 double Properties: Units: Yrs Values: Min 25 Median 39 Max 50 Height: 100x1 double Properties: Units: In Values: Min 60 Median 67 Max 72 Weight: 100x1 double Properties: Units: Lbs Values: Min 111 Median 142.5 Max 202 Smoker: 100x1 logical Values: True 34 False 66 BloodPressure: 100x2 double Properties: Units: mm Hg Description: Systolic/Diastolic Values: Column 1 Column 2 ________ ________ Min 109 68 Median 122 81.5 Max 138 99 ```

The `BloodPressure` variable has a description and the `Age`, `Height`, `Weight`, and `BloodPressure` variables have units.

### Change a Variable Name

Change the variable name for the first variable from `LastName` to `PatientName`.

`T.Properties.VariableNames("LastName") = "PatientName";`

Display the first five rows of the table, `T`.

`T(1:5,:)`
```ans=5×6 table PatientName Age Height Weight Smoker BloodPressure ___________ ___ ______ ______ ______ _____________ "Smith" 38 71 176 true 124 93 "Johnson" 43 69 163 false 109 77 "Williams" 38 64 131 false 125 83 "Jones" 40 67 133 false 117 75 "Brown" 49 64 119 false 122 80 ```

In addition to properties for variable units, descriptions and names, there are table properties for row and dimension names, a table description, and user data.