Create Numeric Arrays

Create Numeric ArraysThis example shows how to create a numeric variable. In the MATLABcomputing environment, all variables are arrays, and by default, numericvariables are of type double (that is, double-precision values). For example,create a scalar value.

A = 100;

Because scalar values are single element, 1-by-1 arrays,

whos A

returns

Name Size Bytes Class Attributes

A 1x1 8 double

To create a matrix (a two-dimensional, rectangular array of numbers), youcan use the [] operator.

B = [12, 62, 93, -8, 22; 16, 2, 87, 43, 91; -4, 17, -72, 95, 6]

When using this operator, separate columns with a comma or space, andseparate rows with a semicolon. All rows must have the same number ofelements. In this example, B is a 3-by-5 matrix (that is, B has three rowsand five columns).

B =12 62 93 -8 2216 2 87 43 91-4 17 -72 95 6

A matrix with only one row or column (that is, a 1-by-n or n-by-1 array) isa vector, such as

C = [1, 2, 3]

or

D = [10; 20; 30]

1-3

tocLanguageSyntax BasicsCreate VariablesCreate Numeric ArraysStore Text in Character StringsEnter Multiple Statements on One LineContinue Long Statements on Multiple LinesCall FunctionsIgnore Function OutputsVariable NamesValid NamesConflicts with Function Names

Case and Space SensitivityCommand vs. Function SyntaxCommand and Function SyntaxesAvoid Common Syntax MistakesPassing Variable Names

How MATLAB Recognizes Command Syntax

Program ComponentsOperatorsArithmetic OperatorsArithmetic Operators and Arrays

Relational OperatorsRelational Operators and ArraysRelational Operators and Empty Arrays

Logical OperatorsElement-Wise Operators and FunctionsBit-Wise FunctionsShort-Circuit Operators

Operator PrecedencePrecedence of AND and OR OperatorsOverriding Default Precedence

Special ValuesConditional StatementsLoop Control StatementsDates and TimesRepresenting Dates and Times in MATLABDates and Dates with Time

Date and Time FunctionsWorking with Date StringsCreating Date Strings In MATLABSpecifying the Fields of a Date StringCreating Multiple Date StringsTime Display in Date Strings

Date String TablesSymbolic Identifiers for Individual FieldsNumeric Identifiers for Predefined Formats

Working with Date VectorsCreating a Date VectorConverting from Date String to Date VectorConverting from Serial Date Number to Date VectorCreating Multiple Date VectorsMilliseconds in Serial Date NumbersExamples of Using Date Vectors

Working with Serial Date NumbersConverting from Date String to Serial Date NumberConverting from Date Vector to Serial Date NumberCreating Multiple Serial Date NumbersUsing Serial Date Numbers For Elapsed TimeExamples of Using Serial Date Numbers

Other ConsiderationsCarrying to the Next FieldSpecifying a Pivot YearDate Vectors vs. Vectors of Date Numbers

Function Summary

Regular ExpressionsOverviewCalling Regular Expression Functions from MATLABMATLAB Regular Expression FunctionsReturning the Desired InformationModifying Parameters of the Search (Modes)

Parsing Strings with Regular ExpressionsStep 1 Identify Unique Patterns in the StringStep 2 Express Each Pattern as a Regular ExpressionStep 3 Call the Appropriate Search Function

Other Benefits of Using Regular ExpressionsParsing or Replacing with Multiple Expressions and StringsReplacing Parts of a StringMatching with Tokens Taken from the StringMatching and Replacing Strings Dynamically

Metacharacters and OperatorsCharacter Type OperatorsAny Character .Selected Characters [c1c2c3]Range of Characters [c1 - c2]Word and White-Space Characters \w, \sNumeric Digits \d

Character RepresentationOctal and Hexadecimal \o, \x

Grouping OperatorsGrouping and Capture (expr)Grouping Only (?:expr)Alternative Match expr1|expr2

Nonmatching OperatorsIncluding Comments (?#expr)

Positional OperatorsStart and End of String Match ^expr, expr$Start and End of Word Match \Exact Word Match \

Lookaround OperatorsUsing the Lookahead Operator expr(?=test)Using the Negative Lookahead Operator expr(?!test)Using the Lookbehind Operator (?