sortx

Sort elements in heatmap row

Syntax

sortx(h,row)

sortx(h,row,direction)

sortx(___,'MissingPlacement',lcn)

sortx(h)

C = sortx(___)

[C,x] = sortx(___)

Description

sortx(h,row) displays the elements in row in ascending order (from left to right). This function sorts the row elements by rearranging the columns. Specify row as one element or as an array of elements from YData. If the first row that you specify has repeating values, then sortx rearranges the remaining columns according to the second row, and so on.

sortx(h,row,direction), where direction is 'descend', sorts the values in descending order instead of ascending order (default). To sort in a unique direction for each row in row, specify direction as an array whose elements are 'ascend' or 'descend'.

sortx(___,'MissingPlacement',lcn) specifies whether to put NaN elements first or last in the sort order. Specify lcn as 'first', 'last', or 'auto'. The default setting is 'auto', which lists NaN elements last for ascending order and first for descending order. Use this option after any of the previous input argument combinations.

sortx(h) displays the elements in the top row in ascending order. If the first row has repeating elements, then sortx rearranges the remaining columns according to the second row, and so on.

C = sortx(___) returns the sorted color data, which is a matrix of values as they appear in the heatmap chart.

[C,x] = sortx(___) also returns the sorted x values in the order they are displayed.

Examples

Display Heatmap Row in Ascending Order

Create a heatmap of utility outages and sort the values in a particular row so that they appear in ascending order, from left to right.

First, create a heatmap. Read the sample file outages.csv into a table. The sample file contains data representing electric utility outages in the United States. The table contains six columns: Region, OutageTime, Loss, Customers, RestorationTime, and Cause. Create a heatmap that shows the different regions along the x-axis and the different outage causes along the y-axis. In each cell, show how many times each region experienced a power outage due to a particular cause.

T = readtable('outages.csv');
h = heatmap(T,'Region','Cause');

Sort the values in the 'winter storm' row so that they appear in ascending order from left to right.

sortx(h,'winter storm')

Display Heatmap Row in Descending Order

Create a heatmap of utility outages and display the values in the 'winter storm' row in descending order by rearranging the columns.

T = readtable('outages.csv');
h = heatmap(T,'Region','Cause');
sortx(h,'winter storm','descend')

Rearrange Heatmap Columns Based on Multiple Rows

Create a heatmap of utility outages and rearrange the columns using values from multiple rows. Sort the columns so that the row 'unknown' appears in ascending order. Since that row contains duplicate values, use the row 'earthquake' to sort the remaining columns.

T = readtable('outages.csv');
h = heatmap(T,'Region','Cause');
sortx(h,{'unknown','earthquake'})

Return Rearranged Heatmap Column Values

Create a heatmap of utility outages and sort the values in the 'winter storm' row so that they appear in ascending order. Return the sorted color data and the column values (x values) in the order that they appear along the x-axis.

T = readtable('outages.csv');
h = heatmap(T,'Region','Cause');
[C,x] = sortx(h,'winter storm')

C = 10×5

     0    12   127    20   135
     0     0     1     0     1
     8    19    49    81    31
     2     9    85    42    18
     0     0    17     3     5
     6    31    23   135   143
     6    32     7    54   102
     0     5     4     4    11
     3    16    22    13    41
     1    18    19    37    70

x = 5x1 cell
    {'SouthWest'}
    {'MidWest'  }
    {'West'     }
    {'SouthEast'}
    {'NorthEast'}

Restore Original Heatmap Column Order

Create a heatmap of utility outages and sort the values in the top row in ascending order by rearranging the columns. Then, restore the original order.

T = readtable('outages.csv');
h = heatmap(T,'Region','Cause');
sortx(h)

Restore the original column order by setting the XDisplayData property of the HeatmapChart object equal to the XData property.

h.XDisplayData = h.XData;

Input Arguments

h — Heatmap

HeatmapChart object

Heatmap to update, specified as a HeatmapChart object.

row — Row to sort

character vector | cell array of character vectors | string array

Row to sort, specified as a character vector, cell array of character vectors, or string array indicating one or more elements from the YData or YDisplayData property of the HeatmapChart object.

Example: sortx(h,'MyRowName') sorts the elements in the row called 'MyRowName' in ascending order.

direction — Direction to sort

'ascend' (default) | 'descend' | cell array of character vectors | string array

Direction to sort, specified as one of these values:

• 'ascend' — Sort all rows in row in ascending order.

• 'descend' — Sort all rows in row in descending order.

• Array — Sort in a unique direction for each row in row. Specify direction as a cell array of character vectors or a string array containing the elements 'ascend' or 'descend'. The array must be the same length as row.

Example: sortx(h,row,{'ascend','descend','ascend'}) sorts the elements in the first row in row in ascending order. If there are any repeating values in the first row, then it breaks ties using the elements of the second row in descending order, and so on.

lcn — NaN placement

'auto' (default) | 'first' | 'last'

NaN placement, specified as one of these values:

• 'auto' — List NaN elements last for ascending order and first for descending order.

• 'first' — List NaN elements first.

• 'last' — List NaN elements last.

Example: sortx(h,row,'MissingPlacement','last')

Output Arguments

C — Sorted color data

matrix

Sorted color data, returned as a matrix. The values in the matrix appear in the same order as they appear on the heatmap.

The ColorDisplayData property of the HeatmapChart object stores the sorted color data. The ColorData property stores the unsorted color data.

x — Rearranged column order

cell array of character vectors

Rearranged column order, returned as a cell array of character vectors.

The XDisplayData property of the HeatmapChart object stores the sorted column order. The XData property stores the unsorted column order.

Algorithms

The sortx function sets and queries these HeatmapChart object properties:

• XDisplayData — Property that stores the x-axis data.

• ColorDisplayData — Property that stores the color display data.

The sortx function also resets the XLimits property.

Version History

Introduced in R2017b