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©2009 by L. Lagerstrom
Intro to Arrays in Matlab
• For an introduction to the basic concepts, see the
“Intro to arrays” video clip
• Three ways to create row vectors
• Matlab’s addressing system
• Creating column vectors
• Creating and addressing 2D arrays
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Note re. Code and Display
•
In the code examples that follow, we will often have the results
displayed simply by leaving off the semicolon at the end of
assignment statements. (The results will be displayed in a
simulated Command window.)
•
In addition, we will assume that the display format has been set
to “format bank” (i.e., results displayed to 2 decimal places),
simply to save space.
•
Finally, the display of the results will have blank lines in it for
readability, but the code that would create those blank lines
(e.g.,
disp(‘ ’)
) will not be shown in the code examples
(again, for readability’s sake).
©2009 by L. Lagerstrom
Three Ways to Create Row Vectors
• By explicitly listing the elements
• By using “colon notation”
• By using the linspace or logspace functions
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View Full Document Matlab code
Command window display
©2009 by L. Lagerstrom
1. Row Vectors by Explicit List
%A. List the values (or "elements")
%within square brackets. (Leave
%off semicolon to display results.)
x = [3 45.2 320 78]
%B. Okay to use commas to separate
%the elements (or commas and spaces)
x = [3,45.2,320,78]
%C. Okay to use math expressions as
%elements
y = pi/6;
z = 4;
x = [56 3/z+2 4*sin(y)]
%D. Row vectors may themselves be
%used as elements in the creation
%of new vectors
x1 = [4 9 2];
x2 = [3 8];
x3 = [x2 54.2 x2 x1]
%E. Square brackets required
x4 = (4 9 2);
%Gives error message
x =
3.00
45.20
320.00
78.00
x =
3.00
45.20
320.00
78.00
x =
56.00
2.75
2.00
x3 =
Columns 1 through 4
3.00
8.00
54.20
3.00
Columns 5 through 8
8.00
4.00
9.00
2.00
Matlab code
Command window display
©2009 by L. Lagerstrom
2. Row Vectors via Colon Notation
%A. Use "colon notation" to specify
%beginning and ending values for the
%elements in the row vector. The
%increment will be 1. Note that
%square brackets not necessary (but
%okay, as are parentheses).
x1 = 1:5
x2 = 3:7
x3 = [3:7]
x4 = (3:7)
%B. We can specify the increment
%by adding a middle value.
x5 = 1:1:5
x6 = 7:2:13
x7 = 7:2:14
x8 = 5:1:2
%Counting down, 5 to 2
x9 = 0:0.25:1
%Nonintegers okay
x10 = 2.3:0.2:3.1
x1 =
1.00
2.00
3.00
4.00
5.00
x2 =
3.00
4.00
5.00
6.00
7.00
x3 =
3.00
4.00
5.00
6.00
7.00
x4 =
3.00
4.00
5.00
6.00
7.00
x5 =
1.00
2.00
3.00
4.00
5.00
x6 =
7.00
9.00
11.00
13.00
x7 =
7.00
9.00
11.00
13.00
x8 =
5.00
4.00
3.00
2.00
x9 =
0
0.25
0.50
0.75 1.00
x10 =
2.30
2.50
2.70
2.90
3.10
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View Full Document Matlab code
Command window display
©2009 by L. Lagerstrom
3. Row Vectors via linspace and logspace
%A. The linspace function generates
%linearly (equally) spaced values.
x1 = linspace(1,5,5)
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This note was uploaded on 02/23/2010 for the course ENG 42325 taught by Professor Lagerstrom during the Spring '10 term at UC Davis.
 Spring '10
 Lagerstrom

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