- •Matlab r2013a стр. 225
- •Continue Long Statements on Multiple Lines
- •Creating and Concatenating Matrices
- •Overview
- •Constructing a Simple Matrix
- •Entering Signed Numbers
- •Specialized Matrix Functions
- •Examples
- •Concatenating Matrices
- •Keeping Matrices Rectangular
- •Matrix Concatenation Functions
- •Examples
- •Generating a Numeric Sequence
- •The Colon Operator
- •Using the Colon Operator with a Step Value
- •Matrix Indexing
- •Accessing Single Elements
- •Linear Indexing
- •Functions That Control Indexing Style
- •Accessing Multiple Elements
- •Nonconsecutive Elements
- •The end Keyword
- •Specifying All Elements of a Row or Column
- •Using Logicals in Array Indexing
- •Logical Indexing – Example 1
- •Logical Indexing – Example 2
- •Logical Indexing with a Smaller Array
- •Single-Colon Indexing with Different Array Types
- •Indexing on Assignment
- •Arithmetic Operators
- •Arithmetic Operators and Arrays
- •Operator Precedence
- •Precedence of and and or Operators
- •Overriding Default Precedence
- •Relational Operators and Arrays
- •Relational Operators and Empty Arrays
- •Overview of the Logical Class
- •Logical Operators
- •Element-Wise Operators and Functions
- •Short-Circuit Operators
- •Precedence of and and or Operators
- •Symbol Reference
- •Asterisk — *
- •Filename Wildcard
- •Function Handle Constructor
- •Class Folder Designator
- •Line Continuation
- •Dynamic Structure Fields
- •Exclamation Point — !
- •Semicolon — ;
- •Array Row Separator
- •Output Suppression
- •Command or Statement Separator
- •Single Quotes — ' '
- •Square Brackets — [ ]
- •Fundamental matlab Classes
- •More About
- •Overview of Numeric Classes
- •Integers
- •Integer Classes
- •Creating Integer Data
- •Arithmetic Operations on Integer Classes
- •Largest and Smallest Values for Integer Classes
- •Integer Functions
- •Floating-Point Numbers
- •Double-Precision Floating Point
- •Single-Precision Floating Point
- •Creating Floating-Point Data
- •Creating Double-Precision Data
- •Creating Single-Precision Data
- •Arithmetic Operations on Floating-Point Numbers
- •Double-Precision Operations
- •Single-Precision Operations
- •Largest and Smallest Values for Floating-Point Classes
- •Largest and Smallest Double-Precision Values
- •Largest and Smallest Single-Precision Values
- •Accuracy of Floating-Point Data
- •Double-Precision Accuracy
- •Single-Precision Accuracy
- •Avoiding Common Problems with Floating-Point Arithmetic
- •Example 1 — Round-Off or What You Get Is Not What You Expect
- •Example 2 — Catastrophic Cancellation
- •Example 3 — Floating-Point Operations and Linear Algebra
- •Floating-Point Functions
- •Creating a Rectangular Character Array
- •Combining Strings Vertically
- •Combining Strings Horizontally
- •Identifying Characters in a String
- •Working with Space Characters
- •Expanding Character Arrays
- •String Comparisons
- •Comparing Strings for Equality
- •Comparing for Equality Using Operators
- •Categorizing Characters Within a String
- •Create a Structure Array
- •Access Data in a Structure Array
- •Concatenate Structures
- •Generate Field Names from Variables
- •Access Data in Nested Structures
- •Access Elements of a Nonscalar Struct Array
- •Create a Cell Array
- •Access Data in a Cell Array
- •Add Cells to a Cell Array
- •Delete Data from a Cell Array
- •Combine Cell Arrays
- •Pass Contents of Cell Arrays to Functions
- •Multilevel Indexing to Access Parts of Cells
- •Related Examples
- •What Is a Function Handle?
- •Creating a Function Handle
- •Maximum Length of a Function Name
- •The Role of Scope, Precedence, and Overloading When Creating a Function Handle
- •Obtaining Permissions from Class Methods
- •Example
- •Using Function Handles for Anonymous Functions
- •Arrays of Function Handles
- •Calling a Function Using Its Handle
- •Calling Syntax
- •Calling a Function with Multiple Outputs
- •Returning a Handle for Use Outside of a Function File
- •Example — Using Function Handles in Optimization
- •Preserving Data from the Workspace
- •Preserving Data with Anonymous Functions
- •Preserving Data with Nested Functions
- •Loading a Saved Handle to a Nested Function
- •Applications of Function Handles
- •Example of Passing a Function Handle
- •Pass a Function to Another Function
- •Example 1 — Run integral on Varying Functions
- •Example 2 — Run integral on Anonymous Functions
- •Example 3 — Compare integral Results on Different Functions
- •Capture Data Values For Later Use By a Function
- •Example 1 — Constructing a Function Handle that Preserves Its Variables
- •Example 2 — Varying Data Values Stored in a Function Handle
- •Example 3 — You Cannot Vary Data in a Handle to an Anonymous Function
- •Call Functions Outside of Their Normal Scope
- •Save the Handle in a mat-File for Use in a Later matlab Session
- •Parameterizing Functions
- •Overview
- •Parameterizing Using Nested Functions
- •Parameterizing Using Anonymous Functions
- •See Also
- •More About
- •Saving and Loading Function Handles
- •Invalid or Obsolete Function Handles
- •Advanced Operations on Function Handles
- •Examining a Function Handle
- •Converting to and from a String
- •Converting a String to a Function Handle
- •Converting a Function Handle to a String
- •Comparing Function Handles
- •Comparing Handles Constructed from a Named Function
- •Comparing Handles to Anonymous Functions
- •Comparing Handles to Nested Functions
- •Comparing Handles Saved to a mat-File
- •Overview of the Map Data Structure
- •Description of the Map Class
- •Properties of the Map Class
- •Methods of the Map Class
- •Creating a Map Object
- •Constructing an Empty Map Object
- •Constructing An Initialized Map Object
- •Combining Map Objects
- •Examining the Contents of the Map
- •Reading and Writing Using a Key Index
- •Reading From the Map
- •Adding Key/Value Pairs
- •Building a Map with Concatenation
- •Modifying Keys and Values in Map
- •Removing Keys and Values from the Map
- •Modifying Values
- •Modifying Keys
- •Modifying a Copy of the Map
- •Mapping to Different Value Types
- •Mapping to a Structure Array
- •Mapping to a Cell Array
Floating-Point Functions
See Floating-Point Functions (R2013a>MATLAB>Language Fundamentals>Data Types>Numeric Types>Function Summary) for a list of functions most commonly used with floating-point numbers in MATLAB.
References
The following references provide more information about floating-point arithmetic.
References
[1] Moler, Cleve, "Floating Points," MATLAB News and Notes, Fall, 1996. A PDF version is available on the MathWorks Web site at http://www.mathworks.com/company/newsletters/news_notes/pdf/Fall96Cleve.pdf
[2] Moler, Cleve, Numerical Computing with MATLAB, S.I.A.M. A PDF version is available on the MathWorks Web site at http://www.mathworks.com/moler/.
R2013a>MATLAB>Language Fundamentals>Data Types>Characters and Strings>Create and Concatenate Strings
Creating Character Arrays
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Creating a Character String Creating a Rectangular Character Array Identifying Characters in a String Working with Space Characters Expanding Character Arrays |
Creating a Character String
Create a string by enclosing a sequence of letters in single quotation marks, such as
myString = 'Hello, world';
If the text contains a single quotation mark, include two quotation marks within the string definition:
otherString = 'You''re right'; % Ответ: otherString = You're right.
In the MATLAB® computing environment, all variables are arrays, and strings are of type char (character arrays).
whos myString
Name Size Bytes Class Attributes
myString 1x12 24 char
Functions such as uint16 convert characters to their numeric codes:
str_numeric = uint16('Hello') % В оригинале - str_numeric = uint16(str).
str_numeric =
72 101 108 108 111
The char function converts the integer vector back to characters:
str_alpha = char([72 101 108 108 111])
str_alpha =
Hello
Creating a Rectangular Character Array
You can join two or more strings together to create a new character array. This is called concatenation and is explained for numeric arrays in the section Concatenating Matrices (R2013a>MATLAB>Language Fundamentals>Matrices and Arrays>Array Creation and Concatenation>Creating and Concatenating Matrices). As with numeric arrays, you can combine character arrays vertically or horizontally to create a new character array.
Alternatively, combine strings into a cell array (R2013a>MATLAB>Language Fundamentals>Data Types>Characters and Strings>Create and Concatenate Strings). Cell arrays are flexible containers that allow you to easily combine strings of varying length.
Combining Strings Vertically
To combine strings into a two-dimensional character array, use either of these methods:
Apply the MATLAB concatenation operator, []. Separate each row with a semicolon (;). Each row must contain the same number of characters. For example, combine three strings of equal length:
dev_title = ['Thomas R. Lee'; ...
'Sr. Developer'; ...
'SFTware Corp.'] % Ниже дается ответ как дополнение к оригиналу:
dev_title =
Thomas R. Lee
Sr. Developer
SFTware Corp.
If the strings have different lengths, pad with space characters as needed. For example:
mgr_title = ['Harold A. Jorgensen '; ...
'Assistant Project Manager'; ...
'SFTware Corp. '] % Ниже дается ответ как дополнение к оригиналу:
mgr_title =
Harold A. Jorgensen
Assistant Project Manager
SFTware Corp.
Call the char function. If the strings are different length, char pads the shorter strings with trailing blanks so that each row has the same number of characters. For example, combine three strings of different lengths:
mgr_title = char('Harold A. Jorgensen', ...
'Assistant Project Manager', 'SFTware Corp.');
The char function creates a 3-by-25 character array mgr_title.
ДОПОЛНЕНИЕ. Последняя команда дает результат аналогичный предыдущим:
mgr_title =
Harold A. Jorgensen
Assistant Project Manager
SFTware Corp. (Конец ДОПОЛНЕНИЯ)