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Overview of today
•
Today:
–
Review of concepts from last time
•
Matrix functions and conditional statements
•
conditional statements
•
For and While loops in Matlab
–
Statistical measures for differential gene
expression
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View Full Document Conditional statements
•
How do we control the flow of a program based on the
state of the variables?
if, else, elseif statement
if
condition1
<dosomethinghere>
elseif
condition2
<dosomethinghere>
else
<dosomethinghere>
end
(any number of elseif‟s can be used, either 1 or 0 else‟s can be used)
Matlab expects elseif but
Perl uses elsif.
Matlab does not accept { }
to wall statements in.
Entire chain of ifelseif
else must end with “end”.
Perl requires { } around
each group of statements.
Conditions
•
How do we express conditions?
For 1x1 number variables (ie, scalars):
a==b, a > b, a < b, a >= b, a <= b, a ~= b
•
What is a condition?
•
A condition is an expression that is valued at either true or false.
(Basically, it‟s a “yes” or “no” question.)
•
You can assign this value to another variable:
Matlab uses ~= for “not
equal”.
Perl uses != or
ne.
is_3_equal_to_4 =
0
is_3_less_than_4 =
1
conditionals.m
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View Full Document Conditional statements
•
How do we control the flow of a program based on the
state of the variables?
if, else, elseif statement
if ( condition )
<dosomethinghere>
elseif
<dosomethinghere>
else
<dosomethinghere>
end
(any number of elseif’s can be use, either 1 or 0 else’s can be used)
Matlab expects elseif but
Perl uses elsif.
Matlab does not accept { }
to wall statements in.
Entire chain of ifelseif
else must end with “end”.
Perl requires { } around
each group of statements.
Conditional statements
Some examples:
conditionals.m
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View Full Document Conditional statements
•
More on expressing conditions
For 1x1 number variables (or single elements of a matrix):
a==b, a > b, a < b, a >= b, a <= b, a ~= b
For strings (matrices of characters):
strcmp(str1, str2), strmatch(str1, strlist), strfind(str1,pattern)
For any matrix (string or number)
isequal(A,B)
(only true if it’s the same size and all corresponding
elements are equal)
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This note was uploaded on 10/21/2011 for the course CSCI 3003 taught by Professor Staff during the Spring '08 term at Minnesota.
 Spring '08
 Staff

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