tail - Get bottom rows of array or table - MATLAB (original) (raw)
Get bottom rows of array or table
Syntax
Description
tail([A](#mw%5F5391357f-affc-4de8-aa98-ecec6b8974ae)) displays the last eight rows of array, table, or timetable A in the Command Window without storing a value.
tail([A](#mw%5F5391357f-affc-4de8-aa98-ecec6b8974ae),[k](#mw%5F4df0abb9-4348-4fa5-9652-3059ba15a16f)) 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 ofA.
Examples
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 99100 100 100 100
Create a table from a file with 1468 rows.
T = readtable("outages.csv","TextType","string"); size(T)
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.
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"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)
Return another table that has the last eight rows of 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
Input data, specified as an array, cell array, table, or timetable.
Number of rows to extract, specified as a positive integer. IfA has fewer than k rows, thentail returns all rows ofA.
Extended Capabilities
Thetail 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)) orgather(tail(A)). These commands still fully evaluate the tall array A, but only return a small subset of the result in memory.
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).
Version History
Introduced in R2016b
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.
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.