# [SWIFT] Let's understand the if statement!

This time, I learned about if, so I will output it.

• The following content is for the output of the learning content, so there may be errors. Please note

# What is an if statement?

*** In a nutshell, if is a syntax that is executed depending on the success or failure of the condition. *** *** The basic writing method is as follows

#### `qiita.rbvar `

``````
if conditional expression{Statement executed when the conditional expression is true}
``````

Let's look at a simple example next.

#### `qiita.rbvar `

``````
1.let value = 5
2.if value <= 10 {

print("value is 10 or less")

}

Execution result: value is 10 or less

``````

If you try to translate this code into Japanese

#### `qiita.rbvar `

``````
if,[If the value of value is 10 or less{}Please execute the method in]It means that
``````

It's very easy and easy to understand! *** By the way, the conditional expression of the if statement must return a Bool type! *** ***

Let's dig deeper into the if statement!

# What is the else clause?

The else clause is a statement that is executed when the *** condition is not met. *** *** Let's look at the basic syntax!

#### `qiita.rbvar `

``````
if conditional expression{Statement executed when the conditional expression is true

}else{
Statement executed when the conditional expression is false
}
``````

Let's look at a simple example next!

#### `qiita.rbvar `

``````
1.let value = ２６
2.if value <= 10 {

print("value is 10 or less")

}else{

print("value is greater than 10")

}
//Execution result: value is greater than 10

``````

Similar to the above, if you try to translate this code into Japanese

#### `qiita.rbvar `

``````
if,[If the value of value is 10 or less{}Please execute the method in.
If not, else{}It means to execute the method in.
``````

You can also connect if statements to the else clause.

#### `qiita.rbvar `

``````
if conditional expression 1{
Statement executed when conditional expression 1 is true

}else if conditional expression 2{
Executed when conditional expression 1 is false and conditional expression 2 is true

}else{
Executed when both conditional expression 1 and conditional expression 2 are false
}
``````

# What is an if-let statement?

The if-let statement is a statement that branches depending on the presence or absence of an optional type value, and if a value exists, the value can be retrieved at the same time.

*** What is Optional type? *** Click here for those who want to deepen the Optional type! Understand the Optional (Wrapped) type!

Let's see the basic writing style!

#### `qiita.rbvar`

``````
if let constant name=Optional type value{
Statement executed if the value exists

}else{
Statement executed when the value does not exist

``````

}

Next, let's look at a simple example.

#### `qiita.rbvar`

``````
let optionalA =Optional("G")

if let X = optionalA {

print("value is\(X)")

}else{
print("Value does not exist")

Execution result:The value is G
``````

# Finally

This time, I output about the if statement. Even if you are a beginner in programming, the syntax is easy to understand and is often used in application development, so I want to master the basics firmly.