Ruby Knowledge Point three: operator

1. Logical operators

(1) Condition 1 | | Condition 2

Condition 1 is false , only need to judge condition 2

(2) Conditions 1 && conditions 2

Condition 1 is true , the condition must be judged 2

2. Range operator

(1) x.. Y from X to Y, including y

(2) X...y the previous element from X to Y, excluding Y

3. How to Handle exception

(1)

Begin

Handling of exceptions may occur

Rescue

Handling when an exception occurs

End

Specify variable name after rescue to get exception object

Such as:

Begin

Handling of exceptions may occur

Rescue = variable referencing an exception object

Handling when an exception occurs

End

Variable names are not specified, and variables that are automatically assigned when an exception occurs are used with the default variable name

Variable	Significance
$!	The last exception that occurred (Exception object)
[Email protected]	Location information for the last occurrence of the exception

(2) post-processing

Begin

Handling of exceptions may occur

Rescue = variable referencing an exception object

Handling when an exception occurs

Ensure

Processing that you want to perform regardless of whether an exception occurred

End

4. Rescue modifier

Expression 1-Rescue expression 2

An exception occurs in Expression 1, and the value of expression 2 becomes the value of the overall expression.

Equivalent notation:

Begin

Expression 1

Rescue

Expression 2

End

Ruby Knowledge Point three: operator