tail
Get bottom rows of array or table
Description
tail(
displays the last eight rows
of array, table, or timetable A
)A
in the Command Window without
storing a value.
returns
the requested rows of B
= tail(___)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 R2016bR2023a: 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.
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