{"id":12490,"date":"2020-02-24T11:33:23","date_gmt":"2020-02-24T19:33:23","guid":{"rendered":"https:\/\/careerkarma.com\/blog\/?p=12490"},"modified":"2023-12-01T02:30:19","modified_gmt":"2023-12-01T10:30:19","slug":"ruby-if-statement","status":"publish","type":"post","link":"https:\/\/careerkarma.com\/blog\/ruby-if-statement\/","title":{"rendered":"Ruby If Statement"},"content":{"rendered":"\n
When you\u2019re programming in Ruby, you may want to run certain code only if a condition is met. For example, you may want to stop a customer from buying a product if there is no stock left in inventory, or only allow a customer to proceed with a purchase if they have filled out all the relevant forms.<\/p>\n\n\n\n
In order to perform these actions, we need to employ the use of an if statement<\/code>. In simple terms, if statements allow Ruby programs to make decisions based on certain criteria. If a condition is met, then the program will do something.<\/p>\n\n\n\n
In this tutorial, we are going to break down the basics of if<\/code> statements in Ruby, discuss the types of conditions you can use, and explore if else<\/code> statements.<\/p>\n\n\n\n
Ruby If Statement<\/h2>\n\n\n\n
If statements can be used to allow a program to make decisions based on a certain set of criteria. For example, you may want to give a customer a discount if they are a senior citizen, or if they have a coupon listed on their account.<\/p>\n\n\n\n
Here is the syntax for an if statement in Ruby:<\/p>\n\n\n\n
if conditions_are_met\n\t\/\/ Run code\nEnd<\/pre><\/div>\n\n\n\n
Let\u2019s use an example to illustrate how if statements work. Let\u2019s say we have a user who is trying to buy a ticket on our online store, and we need to verify if they are 16 or older. Here\u2019s an example of an if statement that will accomplish this goal: <\/p>\n\n\n\n
user_age = 17\nif user_age < 16\n\tputs \"You are not old enough to use this service.\"\nEnd<\/pre><\/div>\n\n\n\n
Our above code returns nothing because our user\u2019s age is 17. But if our user was under the age of 16, we would see this message: <\/p>\n\n\n\n
You are not old enough to use this service.<\/pre><\/div>\n\n\n\n
If Else Statement<\/h2>\n\n\n\n
With an if statement, we only execute code when our requirements are met. However, we may want something else to happen if our conditions are not met.<\/p>\n\n\n\n
For example, let\u2019s say that we want to present a user with a message if they missed filling out the address form field when they were making a purchase. We also want to present them with a message if the form was filled out correctly, so they know their purchase will go through.<\/p>\n\n\n\n
We can use the if else<\/code> statement to implement this in our code. The else<\/code> statement is written after the if<\/code> statement and has no conditions. Here is the syntax for an else block: <\/p>\n\n\n\n
if conditions_are_met\n\t\/\/ Run code\nelse\n\t\/\/ Run other code\nEnd<\/pre><\/div>\n\n\n\n
Let\u2019s use the same example as we used above to illustrate an if statement<\/code>, and add in a message that appears if a user is 16 or older:<\/p>\n\n\n\n
user_age = 17\nif user_age < 16\n\tputs \"You are not old enough to use this service.\"\nelse\n\tputs \"Your purchase is being processed.\"\nEnd<\/pre><\/div>\n\n\n\n
The above code first defines our user\u2019s age, which is 17 in this case. Then, it runs an if<\/code> statement to evaluate whether the user age is less than 16 conditional is true. Since our user is over the age of 16, the program runs the else<\/code> code. In this case, our code returns the following:<\/p>\n\n\n\n
Your purchase is being processed.<\/pre><\/div>\n\n\n\n
We can take this one step further by using an elsif<\/code> statement. This statement gives us the ability to check for another set of criteria if our first statement evaluates to false. For example, we may be operating a movie theater and offer different rates depending on the age of the customer.<\/p>\n\n\n\n
Here\u2019s an example of an elsif<\/code> statement that checks a customer\u2019s age and returns the price they should pay for a ticket:<\/p>\n\n\n\n
There is a lot going on here, so let\u2019s break it down. On the first lines, we define our customer\u2019s age as 17<\/code>, and the ticket price as 0<\/code>. Then, our program executes an if statement to check the age of the customer and set the ticket price accordingly.<\/p>\n\n\n\n
If our customer is 16 or under, they pay $10 for their ticket; if our customer is aged over 16 and under 65, they\u2019ll pay $15; if our customer is over the age of 65, they\u2019ll pay $10.<\/p>\n\n\n\n
In this case, our customer is 17, which means our code will return the following:<\/p>\n\n\n\n
15<\/pre><\/div>\n\n\n\n
Multiple Conditions<\/h2>\n\n\n\n
If you want to check if two things are true at the same time, you can use multiple conditions. In the above example, we illustrated how an if<\/code> statement can be given multiple conditions by checking if a customer\u2019s age was between 16 and 65.<\/p>\n\n\n\n
In Ruby, we use the &&<\/code> (AND<\/code>) operator to separate the conditions we want to check are true. Here\u2019s an example of an if statement with multiple conditions:<\/p>\n\n\n\n
if user_discount == true && age < 5\n\t\/\/ Run code\nEnd<\/pre><\/div>\n\n\n\n
We can use the &&<\/code> operator as many times as we want to check if a certain statement evaluates to be true.<\/p>\n\n\n\n
On the other hand, if we want to check if either one of two or more statements are true, we can use the ||<\/code> (OR<\/code>) operator. This operator would be useful if, for example, we want to run code if a user is either a gold<\/code> or platinum<\/code> customer. Here\u2019s an example of the ||<\/code> operator in action:<\/p>\n\n\n\n
Because our user is on the Gold<\/code> loyalty plan, our code returns the following: <\/p>\n\n\n\n
10<\/pre><\/div>\n\n\n\n
But if our user was not on the Gold<\/code> or Platinum<\/code> loyalty plan, our code would return 0<\/code>.<\/p>\n\n\n\n
Ruby Conditions<\/h2>\n\n\n\n
In the if statement we defined earlier in the tutorial, we checked if a user\u2019s age was 16 or greater, but there are other symbols you can use in an if statement. We call these conditional statements or conditional operators.<\/p>\n\n\n\n
Here is a list of the conditions you can use in your if statements:<\/p>\n\n\n\n
Symbol<\/td>
Definition<\/td><\/tr>
><\/td>
Greater than<\/td><\/tr>
<<\/td>
Less than<\/td><\/tr>
==<\/td>
Equal to<\/td><\/tr>
!=<\/td>
Not equal to<\/td><\/tr>
>=<\/td>
Greater than or equal to<\/td><\/tr>
<=<\/td>
Less than or equal to<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
Conclusion<\/h2>\n\n\n\n
If statements can be used in the Ruby programming language to evaluate whether a statement is true and run code if that statement is true. They can be useful if you have specific code that should only be run when a set of conditions are met. For example, you may want to allow a user to submit a form only if they are logged in.<\/p>\n\n\n\n
In this tutorial, we have discussed the basics of if<\/code> statements in Ruby. We have also explored how you can use else<\/code> and elseif<\/code> to customize your if statements based on multiple possible outcomes.<\/p>\n\n\n\n
Now you\u2019re ready to use if<\/code> statements like a Ruby expert!<\/p>\n\n\n\n