tail

Get bottom rows of array or table

Syntax

tail(A)

tail(A,k)

B = tail(___)

Description

tail(A) displays the last eight rows of array, table, or timetable A in the Command Window without storing a value.

tail(A,k) displays the last k rows of A.

B = tail(___) returns the requested rows of A for either of the previous syntaxes. The data type of B is the same as the data type of A.

Examples

Display Last Eight Rows of Matrix

Create a matrix with 100 rows, and display the last eight rows of the matrix.

If you do not specify an output argument, tail does not return a value. It only displays the bottom of the matrix.

A = repmat((1:100)',1,4);
tail(A)

    93    93    93    93
    94    94    94    94
    95    95    95    95
    96    96    96    96
    97    97    97    97
    98    98    98    98
    99    99    99    99
   100   100   100   100

Display Last Three Rows of Table

Create a table from a file with 1468 rows.

T = readtable("outages.csv","TextType","string");
size(T)

ans = 1×2

        1468           6

Display the last three rows. If you do not specify an output argument, tail does not return a value. It only displays the bottom of the table.

tail(T,3)

      Region          OutageTime        Loss     Customers     RestorationTime           Cause      
    ___________    ________________    ______    __________    ________________    _________________

    "MidWest"      2011-01-02 14:41    364.24    2.8432e+05    2011-01-04 04:43    "winter storm"   
    "SouthEast"    2013-12-20 19:52    2.3096        1038.2    2013-12-20 23:29    "thunder storm"  
    "SouthEast"    2011-09-14 11:55    45.042         11835    2011-09-14 13:28    "equipment fault"

Return Last Eight Rows of Table

Create a table by reading data from a spreadsheet. Display the size of the table, showing that it has 1468 rows.

T = readtable("outages.csv","TextType","string");
size(T)

ans = 1×2

        1468           6

Return another table that has the last eight rows of T.

T2 = tail(T)

T2=8×6 table
      Region          OutageTime        Loss     Customers     RestorationTime           Cause       
    ___________    ________________    ______    __________    ________________    __________________

    "West"         2010-12-04 12:09    245.72     1.074e+05    2010-12-07 13:05    "winter storm"    
    "West"         2013-01-05 05:52         0             0    2013-01-05 06:08    "attack"          
    "West"         2010-12-01 04:12    369.43           NaN    2010-12-01 04:28    "energy emergency"
    "West"         2011-11-21 16:51         0             0    2011-11-21 16:55    "attack"          
    "SouthEast"    2011-01-03 05:52       NaN    2.7596e+05    2011-01-06 05:25    "winter storm"    
    "MidWest"      2011-01-02 14:41    364.24    2.8432e+05    2011-01-04 04:43    "winter storm"    
    "SouthEast"    2013-12-20 19:52    2.3096        1038.2    2013-12-20 23:29    "thunder storm"   
    "SouthEast"    2011-09-14 11:55    45.042         11835    2011-09-14 13:28    "equipment fault" 

Input Arguments

A — Input data

array | cell array | table | timetable

Input data, specified as an array, cell array, table, or timetable.

k — Number of rows to extract

positive integer

Number of rows to extract, specified as a positive integer. If A has fewer than k rows, then tail returns all rows of A.

Extended Capabilities

Tall Arrays

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

The tail function fully supports tall arrays. For more information, see Tall Arrays.

You can use head and tail with tall arrays of any valid underlying data type (single, double, int8, datetime, table, and so on).

If you are unsure whether the result returned by gather(A) will fit in memory, then use gather(head(A)) or gather(tail(A)). These commands still fully evaluate the tall array A, but only return a small subset of the result in memory.

GPU Arrays

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

The tail function fully supports GPU arrays. To run the function on a GPU, specify the input data as a gpuArray (Parallel Computing Toolbox). 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™.

This function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced in R2016b

R2023a: Get bottom rows of array

Display or return the bottom rows of a vector, matrix, multidimensional array, or cell array using tail. In previous releases, tail supports only tables, timetables, and tall arrays.

R2022b: Calling tail without specified output argument does not store output in ans

When you call tail without a specified output argument, tail displays the selected rows of the table but does not store the output in the ans variable. In previous releases, calling tail without a specified output argument causes the output to be stored in ans.

Calling tail in a live script is usually not recommended. Instead, display the table or timetable by typing the variable name with no semicolon. The Live Editor provides a widget that enables you to examine the entire table or timetable. However, if you do call tail in a live script, it is recommended that you assign the output to a variable so that the live script creates a widget for the output.