Clear items from Memory in MATLAB
In this article, we are going to discuss “Clearing items from Memory”, in MATLAB which can be done using clear operation.
The clear operation is used to clear the specified items from memory or from the currently active workspace. It is used to free up the system memory.
Syntax:
clear
clear name1 … nameN
clear -regexp expr1 … exprN
clear(‘a’, ‘b’, ‘c’)
clear([‘a’ ‘b’ ‘c’])
clear functions
clear mex
clear global
clear all
clear keyword
Here,
- clear: This is used to remove all items from the current workspace.
- clear name1, … nameN: This is used to remove the variables such as name1 … nameN from memory.
- clear -regexp expr1 … exprN: This is used to remove all variables matching any of the regular expressions listed. This is used to remove variables only.
- clear(‘a’, ‘b’, ‘c’) and clear([‘a’ ‘b’ ‘c’]): This is used to remove its variables if the specified variables exist in the local environment of the current function.
- clear functions: This is used to remove unlocked functions only. If a function is locked or currently running, it is not cleared from memory.
- clear mex: This is used to clear all MEX files from memory.
- clear global: This is used to clear all global variables.
- clear all: This is used to remove all variables, functions, and MEX files from memory.
- clear keyword: This is used to clear the items indicated by the keyword.
Example 1:
Matlab
% MATLAB code for removes all the % items so its output is blank. % Initializing some items A = 2; B = 4; C = 6; D = 8; % Calling the clear operation to % clear all the above specified items clear % Getting the remaining items whos |
This example will clear all the values.
Example 2:
Matlab
% MATLAB code for Clear operation % Initializing some items A = 2; B = 4; C = 6; D = 8; % Calling the clear operation to % clear B and D items clear B D; % Getting the remaining items whos |
Output:
Variables in the current scope: Attr Name Size Bytes Class ==== ==== ==== ===== ===== A 1x1 8 double C 1x1 8 double Total is 2 elements using 16 bytes
Example 3:
Matlab
% MATLAB code for clear expression values % Initializing some expressions exp1 = 'ab+c' ; exp2 = 'a-c' ; exp3 = '+/gfg' ; % Calling the clear operation to % clear expression exp2 clear -regexp ^exp2; % Getting the remaining expressions whos |
Output:
Variables in the current scope: Attr Name Size Bytes Class ==== ==== ==== ===== ===== exp1 1x4 4 char exp3 1x5 5 char Total is 9 elements using 9 bytes
Example 4:
Matlab
% MATLAB code for clear() % Initializing some items A = 2; B = 4; C = 6; D = 8; % Calling the clear function % to clear items A and C clear ( 'A' , 'C' ); % Again calling the clear function % to clear D items clear ([ 'D' ]); % Getting the remaining items B whos |
Output:
Variables in the current scope: Attr Name Size Bytes Class ==== ==== ==== ===== ===== B 1x1 8 double Total is 1 element using 8 bytes
Example 5:
Matlab
% MATLAB code for clear global variable data % Initializing some items global A; A = 2; B = 4; C = 6; D = 8; % Calling the clear function % to clear global items only clear global % Getting the remaining items whos |
Output:
Variables in the current scope: Attr Name Size Bytes Class ==== ==== ==== ===== ===== B 1x1 8 double C 1x1 8 double D 1x1 8 double Total is 3 elements using 24 bytes
Example 6:
Matlab
% MATLAB code for clear value of variable % Initializing some items global A; A = 2; B = 4; keyword = 6; D = 8; % Calling the clear function % to clear keyword items only clear keyword % Getting the remaining items whos |
Output:
Variables in the current scope: Attr Name Size Bytes Class ==== ==== ==== ===== ===== g A 1x1 8 double B 1x1 8 double D 1x1 8 double Total is 3 elements using 24 bytes
Example 7:
Matlab
% MATLAB code for all types of items are % cleared so nothing is printed as output. % Initializing some items global A; A = 2; B = 4; keyword = 6; D = 8; % Calling the clear function % to clear all items clear all % Getting the remaining items whos |
This example will clear all the values.
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