sortrows - Sort rows of matrix or table - MATLAB (original) (raw)

Sort rows of matrix or table

Syntax

Description

[B](#bt8bwzx-1-B) = sortrows([A](#bt8bwzx-1-A)) sorts the rows of A based on the elements in the first column. By default, sortrows uses ascending sorted order. When the first column contains repeated elements, sortrows sorts according to the values in the next column and repeats this behavior for succeeding equal values.

example

[B](#bt8bwzx-1-B) = sortrows([A](#bt8bwzx-1-A),[column](#bt8bwzx-1-column)) sorts A based on the columns specified in the vectorcolumn. For example, sortrows(A,4) sorts the rows of A in ascending order based on the elements in the fourth column. sortrows(A,[4 6]) first sorts the rows of A based on the elements in the fourth column, then based on the elements in the sixth column to break ties.

example

[B](#bt8bwzx-1-B) = sortrows(___,[direction](#bt8bwzx-1-direction)) sorts the rows of A in the order specified bydirection for any of the previous syntaxes.direction can be 'ascend' (default) for ascending order or 'descend' for descending order.direction can also be a cell array whose elements are'ascend' and 'descend', where each element corresponds to a column that sortrows operates on. For example, sortrows(A,[4 6],{'ascend' 'descend'}) sorts the rows of A in ascending order based on the fourth column, then in descending order based on the sixth column to break ties.

example

[B](#bt8bwzx-1-B) = sortrows(___,[Name,Value](#namevaluepairarguments)) specifies additional parameters for sorting rows. For example,sortrows(A,'ComparisonMethod','abs') sorts the elements of A by magnitude.

example

[[B](#bt8bwzx-1-B),[index](#bt8bwzx-1-index)] = sortrows(___) also returns an index vector that describes the rearrangement of rows such that B = A(index,:).

example

[tblB](#bt8bwzx-1-tblB) = sortrows([tblA](#bt8bwzx-1-tblA)) sorts the rows of a table or timetable.

If tblA is a table, thensortrows sorts tblA in ascending order based on the values in the first variable. If elements in the first variable are repeated, then sortrows sorts by the elements in the second variable, and so on.
If tblA is a timetable, thensortrows sorts the rows oftblA in ascending order based on its row times. However, the rows are sorted only with respect to the row times. If row times are repeated, then sortrows does not sort by the elements in the timetable variables.
Row times of a timetable are datetime orduration values that label the rows along the first dimension of the timetable.

example

[tblB](#bt8bwzx-1-tblB) = sortrows([tblA](#bt8bwzx-1-tblA),'RowNames') sorts a table based on its row names. Row names of a table label the rows along the first dimension of the table. If tblA does not have row names, that is, if tblA.Properties.RowNames is empty, thensortrows returns tblA.

This syntax is not supported when tblA is a timetable.

example

[tblB](#bt8bwzx-1-tblB) = sortrows([tblA](#bt8bwzx-1-tblA),[rowDimName](#bt8bwzx-1-rowDimName)) sorts tblA by row labels rowDimName along the first dimension.

If tblA is a table, then row labels are row names.
If tblA is a timetable, then row labels are row times.

example

[tblB](#bt8bwzx-1-tblB) = sortrows([tblA](#bt8bwzx-1-tblA),[vars](#bt8bwzx-1-vars)) sorts a table by the elements in the variables specified byvars. For example,sortrows(tblA,{'Var1','Var2'}) first sorts the rows oftblA based on the elements in Var1, then by the elements in Var2.

If tblA is a table and it has row names, thenvars can include the row names.
If tblA is a timetable, thenvars can include the row times.

example

[tblB](#bt8bwzx-1-tblB) = sortrows(___,[direction](#bt8bwzx-1-direction)) sorts tblA in the order specified bydirection for any of the previous table syntaxes.direction can be 'ascend' or'descend', which is applied to all specified variables, row names, or row times that sortrows operates on.direction can also be a cell array whose elements are'ascend' and 'descend', where each element corresponds to the specified variables, row names, or row times being sorted on.

example

[tblB](#bt8bwzx-1-tblB) = sortrows(___,[Name,Value](#namevaluepairarguments)) specifies additional parameters for sorting rows of a table or timetable. For example, sortrows(tblA,'Var1','MissingPlacement','first') sorts based on the elements in Var1, ordering missing elements such as NaN at the beginning of the table.

example

[[tblB](#bt8bwzx-1-tblB),[index](#bt8bwzx-1-index)] = sortrows(___) also returns an index vector such thattblB = tblA(index,:).

example

Examples

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Sort Rows of Matrix

Create a matrix and sort its rows in ascending order based on the elements in the first column. When the first column contains repeated elements, sortrows looks to the elements in the second column to break the tie. For repeated elements in the second column, sortrows looks to the third column, and so on.

rng default; A = floor(rand([6 7])*100); A(1:4,1) = 95; A(5:6,1) = 76; A(2:4,2) = 7; A(3,3) = 48

A = 6×7

95    27    95    79    67    70    69
95     7    48    95    75     3    31
95     7    48    65    74    27    95
95     7    14     3    39     4     3
76    15    42    84    65     9    43
76    97    91    93    17    82    38

B = 6×7

76    15    42    84    65     9    43
76    97    91    93    17    82    38
95     7    14     3    39     4     3
95     7    48    65    74    27    95
95     7    48    95    75     3    31
95    27    95    79    67    70    69

Sort the rows of A based on the values in the second column. When the specified column has repeated elements, the corresponding rows maintain their original order.

C = 6×7

95     7    48    95    75     3    31
95     7    48    65    74    27    95
95     7    14     3    39     4     3
76    15    42    84    65     9    43
95    27    95    79    67    70    69
76    97    91    93    17    82    38

Sort the rows of A based on the elements in the first column, and look to the seventh column to break any ties.

D = 6×7

76    97    91    93    17    82    38
76    15    42    84    65     9    43
95     7    14     3    39     4     3
95     7    48    95    75     3    31
95    27    95    79    67    70    69
95     7    48    65    74    27    95

Sort the rows of A in descending order based on the elements in the fourth column, and display the output vector index to see how the rows were rearranged.

[E,index] = sortrows(A,4,'descend')

E = 6×7

95     7    48    95    75     3    31
76    97    91    93    17    82    38
76    15    42    84    65     9    43
95    27    95    79    67    70    69
95     7    48    65    74    27    95
95     7    14     3    39     4     3

Complex Matrix

Create a matrix containing complex numbers, and sort the rows of the matrix in ascending order based on the elements in the first column. Since the magnitudes of A(1,1) and A(3,1) are equal, sortrows computes their angles to break the tie.

A = [1+2i 3+i i; 2+10i 6i 2+5i; 2+i 4 3+3i]

A = 3×3 complex

1.0000 + 2.0000i 3.0000 + 1.0000i 0.0000 + 1.0000i 2.0000 +10.0000i 0.0000 + 6.0000i 2.0000 + 5.0000i 2.0000 + 1.0000i 4.0000 + 0.0000i 3.0000 + 3.0000i

B = 3×3 complex

2.0000 + 1.0000i 4.0000 + 0.0000i 3.0000 + 3.0000i 1.0000 + 2.0000i 3.0000 + 1.0000i 0.0000 + 1.0000i 2.0000 +10.0000i 0.0000 + 6.0000i 2.0000 + 5.0000i

Use the 'real' option to sort the rows of A by their real part. Since A(2,1) and A(3,1) have equal real parts, sortrows uses the imaginary part to break the tie.

C = sortrows(A,'ComparisonMethod','real')

C = 3×3 complex

1.0000 + 2.0000i 3.0000 + 1.0000i 0.0000 + 1.0000i 2.0000 + 1.0000i 4.0000 + 0.0000i 3.0000 + 3.0000i 2.0000 +10.0000i 0.0000 + 6.0000i 2.0000 + 5.0000i

Sort Rows of Cell Array

Create a 6-by-2 cell array of character vectors, and sort its rows. The result is an alphabetized list sorted by both country and name.

A = {'Germany' 'Lukas'; 'USA' 'William'; 'USA' 'Andrew'; ... 'Germany' 'Andreas'; 'USA' 'Olivia'; 'Germany' 'Julia'}

A = 6x2 cell {'Germany'} {'Lukas' } {'USA' } {'William'} {'USA' } {'Andrew' } {'Germany'} {'Andreas'} {'USA' } {'Olivia' } {'Germany'} {'Julia' }

B = 6x2 cell {'Germany'} {'Andreas'} {'Germany'} {'Julia' } {'Germany'} {'Lukas' } {'USA' } {'Andrew' } {'USA' } {'Olivia' } {'USA' } {'William'}

Sort the countries first, then sort the names in descending order.

C = sortrows(A,[1 2],{'ascend' 'descend'})

C = 6x2 cell {'Germany'} {'Lukas' } {'Germany'} {'Julia' } {'Germany'} {'Andreas'} {'USA' } {'William'} {'USA' } {'Olivia' } {'USA' } {'Andrew' }

Sort Rows of Table

Sort the rows of a table by variable values.

Create a table with four variables listing patient information for five people.

LastName = {'Smith';'Johnson';'Williams';'Jones';'Brown'}; Age = [38;43;38;40;49]; Height = [71;69;64;67;64]; Weight = [176;163;131;133;119]; BloodPressure = [124 93; 109 77; 125 83; 117 75; 122 80];

tblA = table(Age,Height,Weight,BloodPressure,'RowNames',LastName)

tblA=5×4 table Age Height Weight BloodPressure ___ ______ ______ _____________

Smith       38       71       176       124     93  
Johnson     43       69       163       109     77  
Williams    38       64       131       125     83  
Jones       40       67       133       117     75  
Brown       49       64       119       122     80

Sort the rows of the table. The sortrows function sorts the rows in ascending order first by the variable Age, and then by the variable Height to break the tie between the two rows with equal ages.

tblB=5×4 table Age Height Weight BloodPressure ___ ______ ______ _____________

Williams    38       64       131       125     83  
Smith       38       71       176       124     93  
Jones       40       67       133       117     75  
Johnson     43       69       163       109     77  
Brown       49       64       119       122     80

Sort Rows of Table by Row Names

Create a table with four variables listing patient information for five people.

LastName = {'Smith';'Johnson';'Williams';'Jones';'Brown'}; Age = [38;43;38;40;49]; Height = [71;69;64;67;64]; Weight = [176;163;131;133;119]; BloodPressure = [124 93; 109 77; 125 83; 117 75; 122 80];

tblA = table(Age,Height,Weight,BloodPressure,'RowNames',LastName)

tblA=5×4 table Age Height Weight BloodPressure ___ ______ ______ _____________

Smith       38       71       176       124     93  
Johnson     43       69       163       109     77  
Williams    38       64       131       125     83  
Jones       40       67       133       117     75  
Brown       49       64       119       122     80

Sort the rows of the table in ascending order based on the row names, and return the index vector that describes how the rows were rearranged.

[tblB,index] = sortrows(tblA,'RowNames')

tblB=5×4 table Age Height Weight BloodPressure ___ ______ ______ _____________

Brown       49       64       119       122     80  
Johnson     43       69       163       109     77  
Jones       40       67       133       117     75  
Smith       38       71       176       124     93  
Williams    38       64       131       125     83

Sort Rows of Table by Variables

Create a table with four variables listing patient information for five people.

LastName = {'Sweet';'Jacobson';'Wang';'Joiner';'Berger'}; Age = [38;43;38;40;49]; Height = [71;69;64;67;64]; Weight = [176;163;131;133;119]; BloodPressure = [124 93; 109 77; 125 83; 117 75; 122 80];

tblA = table(Age,Height,Weight,BloodPressure,'RowNames',LastName)

tblA=5×4 table Age Height Weight BloodPressure ___ ______ ______ _____________

Sweet       38       71       176       124     93  
Jacobson    43       69       163       109     77  
Wang        38       64       131       125     83  
Joiner      40       67       133       117     75  
Berger      49       64       119       122     80

Sort the rows of the table in ascending order by Height, and then in descending order by Weight.

tblB = sortrows(tblA,{'Height','Weight'},{'ascend','descend'})

tblB=5×4 table Age Height Weight BloodPressure ___ ______ ______ _____________

Wang        38       64       131       125     83  
Berger      49       64       119       122     80  
Joiner      40       67       133       117     75  
Jacobson    43       69       163       109     77  
Sweet       38       71       176       124     93

Table with Missing Elements

Create a table with four variables listing patient information for five people. The Weight variable contains missing values.

LastName = {'Sweet';'Jacobson';'Wang';'Joiner';'Berger'}; Age = [38;43;38;40;49]; Height = [71;69;64;67;64]; Weight = [176;NaN;131;133;NaN]; BloodPressure = [124 93; 109 77; 125 83; 117 75; 122 80]; tblA = table(Age,Height,Weight,BloodPressure,'RowNames',LastName)

tblA=5×4 table Age Height Weight BloodPressure ___ ______ ______ _____________

Sweet       38       71       176       124     93  
Jacobson    43       69       NaN       109     77  
Wang        38       64       131       125     83  
Joiner      40       67       133       117     75  
Berger      49       64       NaN       122     80

Sort the rows of the table in ascending order by Weight, placing the rows containing NaN first.

tblB = sortrows(tblA,'Weight','MissingPlacement','first')

tblB=5×4 table Age Height Weight BloodPressure ___ ______ ______ _____________

Jacobson    43       69       NaN       109     77  
Berger      49       64       NaN       122     80  
Wang        38       64       131       125     83  
Joiner      40       67       133       117     75  
Sweet       38       71       176       124     93

Sort Rows of Timetable

Create a timetable, and sort the rows by row times.

TimeDuration = [hours(3) hours(2) hours(1) hours(5) hours(6)]'; TT = timetable(TimeDuration,[98;97.5;97.9;98.1;101],[120;111;119;117;118]);

B = sortrows(TT,'TimeDuration')

B=5×2 timetable TimeDuration Var1 Var2 ____________ ____ ____

1 hr            97.9    119 
2 hr            97.5    111 
3 hr              98    120 
5 hr            98.1    117 
6 hr             101    118

Input Arguments

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`A` — Input array

column vector | matrix

Input array, specified as a column vector or matrix.

`column` — Column sorting vector

nonzero integer scalar | vector of nonzero integers

Column sorting vector, specified as a nonzero integer scalar or vector of nonzero integers. Each specified integer value indicates a column to sort by. Negative integers indicate that the sort order is descending.

`direction` — Sorting direction

'ascend' (default) | 'descend'

Sorting direction, specified as a character vector, string array, or cell array of character vectors containing 'ascend' or'descend'.

If direction is a cell array of character vectors, then the number of entries must match the number of columns or variables being sorted on.

If the column argument and thedirection argument are specified together, thensortrows sorts according todirection, ignoring the signs of the elements incolumn. For example, sortrows(X,[2 3],{'ascend' 'descend'}) first sorts rows in ascending order according to column 2 of X. Then, rows with equal entries in column 2 are sorted in descending order according to column 3.

Data Types: char | string | cell

`tblA` — Input table

table | timetable

Input table, specified as a table or timetable. Each variable intblA must be a valid input to sort or sortrows.

Data Types: table | timetable

`rowDimName` — Name of first dimension of input table or timetable

string scalar | character vector

Name of the first dimension of the input table or timetable, specified as a string scalar or character vector.

If tblA is a table with row names, thenrowDimName is the name of the first dimension of the table. By default, the name of the first dimension is"Row". Dimension names are a property of tables. You can access the dimension names oftblA usingtblA.Properties.DimensionNames.
If tblA is a timetable, thenrowDimName is the name of the vector of row times. You can specify its name when you create a timetable, such asTime or Date. You can also access the dimension names usingtblA.Properties.DimensionNames.

Example: If a table T has row names, and you changed the name of the first dimension using T.Properties.DimensionName{1} = "Name", then sortrows(T,"Name") sorts the table by row name.

Example: If a timetable TT has a time vector namedDate, then sortrows(TT,"Date") sorts the timetable on the dates and times that Date contains.

Data Types: string | char

`vars` — Sorting variables

Sorting variables, specified as a scalar integer, vector of integers, variable name, string array of variable names, cell array of variable names,pattern scalar, or logical vector. vars indicates the table variables to sort by.

If you do not specify the direction argument, the sign of the elements in vars determines the sorting direction of the variables. If an element is a positive integer, thensortrows sorts the corresponding variable intblA in ascending order. If an element is a negative integer, then sortrows sorts the corresponding variable in tblA in descending order. Otherwise, if you specify the direction argument, sortrows ignores the sign of vars and sorts the specified variables according to direction.

Example: sortrows(tblA,["Height","Weight"]) sorts the rows of tblA in ascending order, first by the variableHeight, then by the variableWeight to break ties.

Example: sortrows(tblA,"X" + wildcardPattern) sorts the rows of tblA are in ascending order by the table variables whose names begin with the letter "X", using a wildcard pattern to match the remaining letters in their names.

Example: sortrows(tblA,[1 4]) sorts by the first variable of tblA in ascending order, then sorts by the fourth variable to break ties.

Example: sortrows(TT,["Time","X"]) sorts the row times of timetable TT in ascending order first, then sorts by the table variable X to break ties.

Name-Value Arguments

Specify optional pairs of arguments asName1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: sortrows(A,'MissingPlacement','last')

`MissingPlacement` — Placement of missing values

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

Placement of missing values (NaN,NaT, <undefined>, andmissing) specified as the comma-separated pair consisting of 'MissingPlacement' and one of the following:

'auto' — Missing elements are placed last for ascending order and first for descending order.
'first' — Missing elements are placed first.
'last' — Missing elements are placed last.

`ComparisonMethod` — Element comparison method

'auto' (default) | 'real' | 'abs'

Element comparison method for numeric input, specified as the comma-separated pair consisting of 'ComparisonMethod' and one of the following:

'auto' — Sort rows ofA by real(A) whenA is real, and sort byabs(A) when A is complex.
'real' — Sort rows ofA by real(A) whenA is real or complex. If a column ofA has elements with equal real parts, then use imag(A) to break ties.
'abs' — Sort rows ofA by abs(A) whenA is real or complex. If a column ofA has elements with equal magnitude, then use angle(A) in the interval (-π,π] to break ties.

Output Arguments

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`B` — Sorted array

vector | matrix | multidimensional array

Sorted array, returned as a vector, matrix, or multidimensional array.B is the same size as A.

`tblB` — Sorted table

table | timetable

Sorted table, returned as a table or timetable with the same variables astblA.

Data Types: table | timetable

`index` — Sort index

index vector

Sort index, returned as an index vector. The sort index describes the rearrangement of the rows in the input such that B = A(index,:).

The sortrows function uses a stable sorting algorithm. So, when the input contains repeated values, the sort index preserves the original order from the input, regardless of sorting direction. For example, if A = [1 1; 2 2; 1 2; 2 2], then [Ba,Ia] = sortrows(A,'ascend') returns the sort index Ia = [1; 3; 2; 4] and [Bd,Id] = sortrows(A,'descend') returns the sort index Id = [2; 4; 3; 1].

Data Types: double

Extended Capabilities

Tall Arrays

Calculate with arrays that have more rows than fit in memory.

Thesortrows function supports tall arrays with the following usage notes and limitations:

Sorting by row names is not supported.

For more information, see Tall Arrays.

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

The first input argument must not be a cell array.
If A is complex with all zero imaginary parts, then MATLAB® might convert A toreal(A) before callingsortrows(A). In this case, MATLAB sorts the rows of A byreal(A), but the generated code sorts the rows ofA by abs(A). To make the generated code match MATLAB, use sortrows(real(A)) orsortrows(A,'ComparisonMethod','real'). See Code Generation for Complex Data with Zero-Valued Imaginary Parts (MATLAB Coder).
If tblA is a table or timetable, then the input argument vars must be constant.
If tblA is a table or timetable, and it has a variable that is a cell array of character vectors with multiple columns, then you cannot sort tblA using the values in that variable.
The vars input argument does not support pattern expressions.

GPU Code Generation

Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

Usage notes and limitations:

The first input argument must not be a cell array.
If A is complex with all zero imaginary parts, then MATLAB might convert A toreal(A) before callingsortrows(A). In this case, MATLAB sorts the rows of A byreal(A), but the generated code sorts the rows ofA by abs(A). To make the generated code match MATLAB, use sortrows(real(A)) orsortrows(A,'ComparisonMethod','real').

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

The sortrows function supports GPU array input with these usage notes and limitations:

Sorting cell arrays is not supported.
Sparse inputs are not supported.

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

Usage notes and limitations:

Sorting cell arrays is not supported.
Table, timetable, datetime and duration inputs are not supported.

For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced before R2006a

sortrows - Sort rows of matrix or table - MATLAB (original) (raw)

Syntax

Description

Examples

Sort Rows of Matrix

Complex Matrix

Sort Rows of Cell Array

Sort Rows of Table

Sort Rows of Table by Row Names

Sort Rows of Table by Variables

Table with Missing Elements

Sort Rows of Timetable

Input Arguments

A — Input array

column — Column sorting vector

direction — Sorting direction

tblA — Input table

rowDimName — Name of first dimension of input table or timetable

vars — Sorting variables

Name-Value Arguments

MissingPlacement — Placement of missing values

ComparisonMethod — Element comparison method

Output Arguments

B — Sorted array

tblB — Sorted table

index — Sort index

Extended Capabilities

Tall Arrays

C/C++ Code Generation

GPU Code Generation

Thread-Based Environment

GPU Arrays

Distributed Arrays

Version History

`A` — Input array

`column` — Column sorting vector

`direction` — Sorting direction

`tblA` — Input table

`rowDimName` — Name of first dimension of input table or timetable

`vars` — Sorting variables

`MissingPlacement` — Placement of missing values

`ComparisonMethod` — Element comparison method

`B` — Sorted array

`tblB` — Sorted table

`index` — Sort index