Operators

Phone Operator

Surgical Operator

Smooth Operator

Logical Operators: 1 = True, 0 = False

&& AND

1 && 1

true && true 		1

true
1 && 0

true && false 		0

false
0 && 1

false && true 		0

false
0 && 0

false && false 		0

false

|| OR

1 || 1

true || true 		1

true
1 || 0

true || false 		1

true
0 || 1

false || true 		1

true
0 || 0

false || false 		0

false

~ NOT

~0

~ false 		1

true
~1

~ true 		0

false

Logical Operators

Relational Operators

> greater than

3 > 1 true - 1
-2 > -6 true - 1
4 > 4 false - 0

< less than

3 < 9 true - 1
-4 < 0 true - 1
6 < 2 false - 0

>= greater than or equal to

2 >= 1 true - 1
5 >= 5 true - 1
1 >= 3 false - 0

<= less than or equal to

7 <= 10 true - 1
6 <= 6 true - 1
-1 <= -3 false - 0

== equal

1 == 1 true - 1
-3 == -3 true - 1
2 == -1 false - 0

~= not equal

3 ~= 4 true - 1
0 ~= 2 true - 1
6 ~= 6 false - 0

Multiple Conditions

-3 < x < 5

while x > -3 && x < 5
x >= -5, x not equal to 0

while x >= -5 && x ~= 0
x odd but not negative

while mod(x,2) == 1 && x >= 0
x even or negative

while ~mod(x,2) || x < 0
x is 'yes' or 'maybe'

while x == 'yes' || x == 'maybe'
x is not 'no' and not 'maybe'

while x ~= 'no' && x ~= 'maybe'
x is odd and not 3 OR x is even and positive

while (mod(x,2) == 1 && x ~= 3) || (~mod(x,2) && x > 0)
x is 'red' or 'blue' or 'green' AND x is 'orange' or 'yellow' or 'pink'

while (x == 'red' || x == 'blue' || x == 'green') && (x == 'orange' || x == 'yellow' || x == 'pink')

Array Index Logic

A = randi(15,5)
B = A < 9
A(B)
A(A<9 && A>2)
A(A<9 && ~mod(A,2))
A(A<9 && ~mod(A,2) & A~=2)
A(A>10) = 10

While Loop

Syntax

while expression
    statements
end

Process

n = 4;
f = n;
while n > 1
    n = n - 1;
    f = f * n;
end

1st Pass

n = 4
f = 4
4 > 1 is true -- loop continues
n = n - 1 = 4 - 1 = 3
f = f * n = 4 * 3 = 12

2nd Iteration

n = 3
f = 12
3 > 1 is true -- loop continues
n = n - 1 = 3 - 1 = 2
f = f * n = 12 * 2 = 24

3rd Iteration

n = 2
f = 24
2 > 1 is true -- loop continues
n = n - 1 = 2 - 1 = 1
f = f * n = 24 * 1 = 24

4th Iteration

n = 1
f = 24
1 > 1 is false -- loop breaks

Flow Control

break

limit = 0.8;
s = 0;

while 1
    tmp = rand;
    if tmp > limit
        break
    end
    s = s + tmp;
end

continue

A = zeros(1,9);
n = 10;
while n > 0
    n = n - 1;
    if n == 3
        continue;
    end
    A(1,i) = i;
end
A

Nested While Loops

% brownEggs = 1
% whiteEggs = 2
% blueEggs = 3
% goldEggs = 4

A = randi(4,10)
n = 10;
while n > 0
    m = 10;
    while m > 0
        if A(m,n) == 4
            A(m,n) = 1000;
        end
        m = m - 1;
    end
    n = n - 1;
end
A

Examples

Factorial

n = 10;
start = n;
f = n;
while n > 1
    n = n-1;
    f = f*n;
end
fprintf('%d! = %d',start,f);

Random iterations

n = .5;
m = 0;
while n < .95 && n > .05
    n = rand;
    m = m + 1;
end
fprintf('You made it through the loop %d times\n',m)

Random iterations

m = .5;
n = .5;
hold on
while (m < .9 && m > .1) || (n < .9 && n > .1)
    n = rand;
    m = rand;
    plot(m,n,'*r')
    plot(n,m,'*b')
end
m = .5;
n = .5;
hold on
while (m < .9 && m > .1) || (n < .9 && n > .1)
    n = rand;
    m = rand;
    plot(m,n,'*c')
    plot(n,m,'*g')
end

Algorism and Bushism of the Day

"I know the human being and fish can co-exist peacefully."

"Machismo gracias" - Thanking someone while campaigning for re-election as Vice President

Machismo = strong or aggressive masculine pride.

Lesson of the Day

Linear vs Circular Thinking

How to become a genius



Word of the day

Bauhaus

Ziggy Stardust



The End