E7_Lecture5_Su10+posted

# E7_Lecture5_Su10+posted - Introduction to arrays Examples:...

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E7 L3 1 Introduction to arrays Introduction to arrays Examples: 2-dimensional arrays (2 rows, 3 columns) (3 rows, 3 columns) 1.2 3.2 1.0 3.1 92 0.0 d - = 1 4 6 7 2 5 8 4 3 e =

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E7 L4 2 2-dimensional arrays 2-dimensional arrays A rectangular arrangement of numbers is called an array. 2 1 2 4 5 - Example: 3-by-2 array. (3 rows, and 2 columns) (3,1) element (3 rd row, and 1 st column) Matlab 2-D convention: ( Row , Column)
E7 L4 3 Creating arrays – manual construction Creating arrays – manual construction Example 1: >> A = [ 2 1 ; -2 3 ; 4 5 ] A = 2 1 -2 3 4 5 2 1 2 3 4 5 A = - The semicolon is used to demark rows

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E7 L4 4 Creating arrays – manual construction Creating arrays – manual construction Example 1: carriage return <CR> is also used to demark rows >>A = [ 2 1 -2 3 4 5 ] A = 2 1 -2 3 4 5
Example 1: >>A = [[ 2 ; -2 ; 4 ] , [ 1 ; 3 ; 5 ] ] A = 2 1 -2 3 4 5 E7 L4 5 Creating arrays – manual construction Creating arrays – manual construction first column second column

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Example 1: >>A = [[ 2 ; -2 ; 4 ] [ 1 ; 3 ; 5 ] ] A = 2 1 -2 3 4 5 E7 L4 6 Creating arrays – manual construction Creating arrays – manual construction first column second column comma is not needed
Example 1: >> A = [[ 2;-2 ;4 ] . .. [ 1 ; 3 ; 5 ] ] A = 2 1 -2 3 4 5 E7 L4 7 Creating arrays – manual construction Creating arrays – manual construction “...” - allows a new line without a <CR>

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Example 1: >>A = [[ 2;-2 ;4 ] [ 1 ; 3 ; 5 ] ] A = 2 -2 4 1 3 5 E7 L4 8 Creating arrays – manual construction Creating arrays – manual construction <CR> means a new row
zeros, ones and rand commands zeros, ones and rand commands E7 L3 9 >> A = ones(2,3) A = 1 1 1 1 1 1 >> B = zeros(2,2) B = 0 0 0 0 Matlab 2-D convention: >> r = 3*ones(1,5) r = 3 3 3 3 3 (rows, columns)

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Array concatenation Array concatenation E7 L3 10 >> A = ones(2,3) A = 1 1 1 1 1 1 >> B = zeros(2,2) B = 0 0 0 0 >> C = [ A B ] C = 1 1 1 0 0 1 1 1 0 0
Array concatenation Array concatenation E7 L3 11 >> C = [ A B ] C = 1 1 1 0 0 1 1 1 0 0 C is the array formed by stacking A “next to” B Once constructed, C does not “know” that it came from two arrays. No partitioning information is maintained.

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Array concatenation Array concatenation E7 L3 12 C = 1 1 1 0 0 1 1 1 0 0 r = 3 3 3 3 3 >> D = [ C ; r ] D = 1 1 1 0 0 1 1 1 0 0 3 3 3 3 3
Array concatenation Array concatenation E7 L3 13 >> D = [ C ; r ] D = 1 1 1 0 0 1 1 1 0 0 3 3 3 3 3 D is the array formed by stacking C “on top of” r

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## This note was uploaded on 08/14/2010 for the course E 7 taught by Professor Patzek during the Summer '08 term at University of California, Berkeley.

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E7_Lecture5_Su10+posted - Introduction to arrays Examples:...

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