Page 3Overview
Description and execution: Python and Ruby are highly interactive; ○ Compilation and execution: Pascal, C, fast. N local execution, such as C, C ++; N virtual machine execution, such as Java, C #. ○ Dynamic languages, such as JavaScript and Ruby; ○ Static languages, such as C ++ and Java. |
Language ○ Syntax Keywords Description ○ Pragmatic |
Matz 1993
Ruby ['ru: BI] (Ruby)
Ruby draws on Perl regular expressions, Python's simplicity and readability, Smalltalk's pure object-oriented syntax and single inheritance, LISP's infinitely nested syntax, Java's thread... |
Page 14Getting started
XP
CMD
C: \ Documents ents and Settings \ Administrator> ruby-V Ruby 1.8.6 (patchlevel 111) [i386-mswin32] |
Method 1:RubyCommand
C: \ Documents ents and Settings \ Administrator> ruby-e 'print "Hello World "' Hello World |
Ruby runs ruby;
-E: Execute the subsequent Ruby script.Program;
Print print display;
Hello, world.
Method 2:IRBInteractive execution
C: \ Documents ents and Settings \ Administrator> IRB IRB (main): 001: 0> Print "Hello World" Hello world => Nil IRB (main): 002: 0> exit |
Exit: exit the IRB interactive environment.
Method 3: CreateRubyScript
C: \ Documents ents and Settings \ Administrator> copy con helloworld. Rb Print "Hello World" Print "3*7 =", 3*7 ^ Z Copied 1Files. C: \ Documents ents and Settings \ Administrator> helloworld. Rb Hello world3 * 7 = 21 |
Page 17IDE
○ Eclipse + RDT (Ruby development tools)
○ Freeride + scite
1. Edit Ruby in sciteCode;
2. Save. RbFile;
3. In the menu bar, choose tools> RUN or F5;
Page 18Syntax
1.Note
Single line comment # multi-line comment = begin = end
Ruby embedded document (rdoc) annotation, using the RI command to generate documents from the source file.
Rdoc is embedded in Ruby code and can be converted to HTML documents.
RI command to view the function description and class description. Function Description and class description should be placed in = begin and = end. Note: "= begin" must be written at the beginning of the line. That is to say, the first six characters in this line are "= begin". spaces are not allowed before.
2.Branch
The statement ends with a semicolon.
Multiple statements in one row are separated by semicolons. The last statement can be omitted. A line break indicates that a row ends.
The statement is too long. You can use the '\' symbol at the end of the line to represent the continued row.
3.Delimiter
Name |
Symbol |
Purpose |
Semicolon |
; |
Used to separate multiple statements in a row |
Parentheses |
() |
Raise the priority; include the parameter list when defining a method |
Space |
|
Delimiter; In the case where () can be omitted, replace () |
Comma |
, |
Separate multiple parameters |
Point |
. |
Separate an object from its Method |
Two colons |
:: |
The domain identifier that separates a module (class) from its constants. |
4.Keywords
The keywords in ruby are as follows:
Module definition: |
Module |
Exception Handling: |
Rescue, ensure |
Class Definition: |
Class |
Object Reference: |
Super, self |
Method definition: |
Def, UNDEF |
Block start: |
Begin/end |
Check type: |
Defined? |
Embedded Module: |
Begin, end |
Logical value and null value: |
True, false, Nil |
File-related: |
_ File __,__ line __ |
Logical judgment: |
Not, And, or |
Method return: |
Return |
Condition Statement: |
If, then, else, elsif, case, when, unless |
Alias: |
Alias |
Loop statement: |
For, in, while, until, next, break, do, redo, retry, yield |
The begin module is equivalent to a macro in the C language, and the end module is used for some final work. With
Require, include, should cancel the syntax definition of begin and end.
5.Operator
6.Identification name:
Constants, variables, methods, classes, and modules;
Case Sensitive;
The first character indicates the usage of the name.
Local variables, method parameters, and method names |
It must start with a lowercase letter or underscore; |
Class Name, Module name, and constant |
It must start with an uppercase letter. |
Global Variables |
Prefix with the dollar sign $; |
Instance variables |
Starting; |
Class variable |
Start; |
The first letter can be followed by any combination of letters, numbers, and underscores;
@ Cannot be followed by numbers directly.
Ruby program code is represented by a 7-bit acⅱ code, which supports eight-bit coding systems such as EUC, sjis, and UTF-8 through language extensions. Ruby2.0 supports 16-bit Unicode encoding.
7.Class Library
You can directly use:
I) KEYWORDS;
Ii) classes and methods in the require or include class libraries;
Iii) methods inherited from the parent class.
Puts |
Automatic line feed after each parameter |
Print |
Do not automatically wrap, use "\ n" for line feed" |
Printf |
Output by format, not automatically wrap |
Gets |
Read data from the keyboard or file |
C: \ Documents ents and Settings \ Administrator> ruby-e 'puts "hello", "world "' Hello World |
C: \ Documents ents and Settings \ Administrator> ruby-e 'printf "number: % F", 100' No.: 3.200000 |
Note: printf parameters are separated by commas.
C: \ Documents ents and Settings \ Administrator> ruby-e 'printf "number: % 4.3f, string % s ", 1.5," Hello World "' Number: 1.500, string Hello World |
8.Data Type
Type |
Category |
Description and example |
Number |
Integer |
0 octal, 0x hexadecimal, 0b binary |
Floating Point Type |
String |
Single quotes'' |
|
Double quotation mark "" |
|
Array |
Starting from 0, each element can be of different types |
Example [2.4, "thank you", [a, B, c], 78] |
Interval |
1. 5 |
1, 2, 3, 4, 5 |
1... 5 |
1, 2, 3, 4 |
Regular Expression |
|
|
9.Value assignment
Values of the exchange variables A and B:
A, B = B,;
Note:
A = (B = 1 + 2) + 3 # A = 6, B = 3
Comma (,), from left to right, assigned to A, B, and C respectively.
X = 0 # x = 0
A, B, c = x, (x + 1), (X + 2) # A = 0, B = 1, C = 2
10.Conditional operation
= |
Equal |
! = |
Not equal |
Eql? |
Compare the values and types of the two objects. |
Equal? |
Compare whether two objects have the same address in the memory |
< |
Less |
> |
Greater |
<= |
Less than or equal |
> = |
Greater than or equal |
= ~ |
Match Regular Expression |
!~ |
Assertion does not match the Regular Expression |
=== |
The object on the right is within the left range. Puts (0 .. 9) ===3.14 # True puts ('A'... 'F') ==='c' # True |
<=> |
Compare the sizes of two objects, greater than 1, equal to 0, less than-1. |
In Ruby, nil and false are false, while others are true.
11.Judgment statement
- Single line if statement
|
If then end |
() If |
- Multi-line if statement
|
If elsif else end |
- Unless Condition Statement
|
Unless |
If not |
- Case branch Condition Statement
|
Case When When Else End |
12.Loop statement
Single Row while |
(Statement 1; Statement 2; statement ...) While Condition |
Multiline while |
While Condition Statement End |
Until |
Until jump out of the loop Condition Statement Until condition = while not (condition) |
For... In Loop |
For variable in object Statement 1; Statement 2; statement... End |
Break, next & redo & retry
In the circular body, if you encounter:
Break |
Jump out of the current layer loop; |
Next |
Ignore the remaining part of this loop and start the next loop; |
Redo |
Start the loop again, or start from this time; |
Retry |
Start the loop body. |
Times, upto, downto, each, step
Statement |
Running result |
3. Times {print "Hi! "} |
# Hi! Hi! Hi! |
1. upto (9) {| I | print I if I <7} |
#123456 |
9. downto (1) {| I | print I if I <7} |
#654321 |
(1 .. 9). Each {| I | print I if I <7} |
#123456 |
0. Step (11,3) {| I | print I} |
#0369 |
C: \ Documents ents and Settings \ Administrator> IRB IRB (main): 001: 0> 1. upto (9) {| I | print I if I <7} 123456 => 1 IRB (main): 002: 0> 9. downto (1) {| I | print I if I <7} 654321 => 9 IRB (main): 003: 0> (1 .. 9). Each {| I | print I if I <7} 123456 => 1 .. 9 IRB (main): 004: 0> 0. Step (11,3) {| I | print I} 0369 => 0 |
13. Exception
Java
Try... Catch... Finally... Throw
Ruby
Begin/end... Rescue... Ensure... Raise
Retry can be used in rescue. You can only use rescue or ensure. when both are used, rescue must be before ensure.
14. threads