Ruby basic code Experience Sharing

The learning of Ruby is the same as that of other programming languages. Here we will introduce how to write the in and END in the basic Ruby code.

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Basic Ruby code: BEGIN Block

Code in the BEGIN block is executed before all code is executed. Ruby allows you to set multiple BEGIN blocks and execute the code in the blocks in the displayed order. C # note the following code

1. BEGIN
2. {
3. Print "OnInit (object sender,
   EventArgs args) \ n"
4. }
5. BEGIN
6. {
7. Print "OnLoad (object sender,
   EventArgs args) \ n"
8. }
9. Print "Running"

The above code looks pretty good. Unfortunately, the above Code segment will have a parse error. The correct code should be

 
 

  
  
BEGIN{  
  
  
print "OnInit(object sender, 
EventArgs args)\n"  
  
  
}  
  
  
BEGIN{  
  
  
print "OnLoad(object sender,
 EventArgs args)\n"  
  
  
}  
  
  
print "Running" 
 
 

As shown in the preceding code snippet, the code can be correctly executed only when the starting braces and the in identifier are in the same row block. At the same time, the BEGIN block is not affected by any control structure, because as long as the BEGIN block appears, it will be executed only once.

 
 

  
  
I = 0
  
  
While I <10
  
  
# While processing the loop structure
The code in the block is still executed only once.
  
  
BEGIN {
  
  
Print "OnInit (object sender,
EventArgs args) \ n"
  
  
}
  
  
I + = 1
  
  
End
  
  
If false
  
  
# BEGIN is completely unaffected by if,
As long as the BEGIN block appears, it will be executed.
  
  
BEGIN {
  
  
Print "OnLoad (object sender,
EventArgs args) \ n"
  
  
}
  
  
End
  
  
Print "Running"
 
 

Based on the principle that only BEGIN is executed and BEGIN is executed before all code is executed, even if the code appears before the BEGIN block, the code will still be executed after the BEGIN block is executed. For example, the output result of the following code snippet is still OnInit-OnLoad-Running.

 
 

  
  
print "OnLoad(object sender, 
EventArgs args)\n"  
  
  
BEGIN{  
  
  
print "OnInit(object sender,
 EventArgs args)\n"  
  
  
}  
  
  
print "Running" 
 
 

END Block of Ruby basic code

The END block is opposite to the BEGIN block. It is executed after all code is executed. When multiple END blocks are executed, the first END block is executed. In addition, although the END block is not affected by the while, the if block may be used to control the execution of the END block. For example, the output result of the following code is Start-Load-Unload.

 
 

  
  
If false
  
  
END {
  
  
# Never output
  
  
Print "Init"
  
  
}
  
  
End
  
  
END {
  
  
# Final output
  
  
Print "Unload \ n"
  
  
}
  
  
END {
  
  
# Output before Unload
  
  
Print "Load \ n"
  
  
}
  
  
# First output
  
  
Print "Start \ n"
 
 

The preceding section describes the basic Ruby code.