The expression is evaluated once and compared with the values of each case label.
Ruby switch case example.
It is similar to the switch keyword in another programming.
When you write x y y in ruby you re asking does y belong in the group represented by x this is a very general statement.
Match values and ranges of values with this statement.
The case statement is a multiway branch statement just like a switch statement in other languages.
Are executed until break is encountered.
There are 3 important keywords which are used in the case statement.
Ranges strings and regexp use the case statement.
This example shows that case statements not only match an item s value but also its class this is possible because under the hood ruby uses the operator aka.
Basically if elsif else notice there s nothing after the word case.
Let s see an example where we want to print some message depending on what range a value falls in.
There is one potential problem with the if else statement which is the complexity of the program increases whenever the number of alternative path increases.
For example if the value of the expression is equal to constant2 statements after case constant2.
Why do we need a switch case.
The following case example detects where a number falls amongst a group of different ranges.
How does the switch statement work.
The case statement is more flexible than it might appear at first sight.
Ruby case ranges.
If there is a match the corresponding statements after the matching label are executed.
Ruby uses case and when where others use switch and case.
Case capacity when 0 you ran out of gas when 1 20 the tank is almost empty.
Variable case when bool condition statements when bool condition statements else the else clause is optional statements end if you assigned variable before the case the variable now has the value of the last executed statement or nil if there was no match.
The three equals operator.
The expression specified by the when clause is evaluated as the left operand.
Score 70 result case score when 0 40 then fail when 41 60 then pass when 61 70 then pass with merit when 71 100 then pass with distinction else invalid score end puts result.
Quickly find a gas station when 21 70 you should be ok for now.
A quick tour of the operator.
It provides an easy way to forward execution to different parts of code based on the value of the expression.
