Go Conditional Statements and Loops

Conditional statement is those statement, which is used to execute code on a certain condition. Unlike C or Java conditional statement, conditions are not required to be written inside parenthesis in Go.

Lets dive into different conditional statement. Go has following conditional statements are:

1. If condition
2. If-else condition
3. If-else if-else condition

1. If condition:

If condition used to check true statement only, means if condition is true then the enclosed code will be executed other wise do nothing.

Suppose we've a variable with value as "Mango" and we want some task to perform while condition is true, so above line of code will execute with true condition and will print the message. If the condition isn't true then the code will do nothing.

2. if-else condition:

        Another form of conditional statement is "If-else" condition, it has two part, the first part will execute while the condition will be true otherwise the second part will be execute automatically.
Let's take an example.

Here we first check a condition for fruit, is fruit equal to Mango? And the fruit variable contain Orange, so the condition will be failed and else part code will be execute automatically and print on console.
"Fruit is different from Mango"

3. If-else if-else condition:

       This type of conditional statement checks multiple condition. we can also say that the multiple "if-else".

As we can see that we're using multiple "if else" condition. The code will be execute where it matches the condition, and at last if there isn't match with anyone condition that time else part will be execute automatically.

Short Statement with if condition:

Another variants for if statement, we can check condition with pre-assigned value to variable with single if statement. Lets take an above example as short statement in if condition.

In above example we first assign value to fruit then we're checking condition in single if statement. When we assign value to variable we put semicolon(;) so that Go compiler can understand that this code is use to assign value then checks condition statement will be execute.

Note: Go does not support ternary operator like C.

We have only the one way, "if condition" to achieve this(ternary operator). see below screen.

Switch Statement:

Switch statement is an alternate for multiple if-else condition, it uses case instead of multiple else if check condition. It executes matched case content with conditional expression.
Unlike C, C++ and Java, there is no need to use break statement in each cases. Go compiler adds automatically.

Loops

Loops are a block of content which execute again and again until the condition statement has been failed. Unlike C, C++ and Java there is no while and do while loop. Go has only one loop named as for loop. Also Go loop does not uses parenthesis before and after statement.

Above screen shows simple For loop which executes "Println()" six times. In Above example, it initialize 0 (zero) to variable i then it checks, is i value less than 5 (condition true until i hold value 6). If condition return true then underlined code will be execute then after it increases i value.

Note:- All statements of  For loop are optional.

There are different ways through which we can use For loop in our code. see below picture. All syntax are valid code.

For Range

In Go there is another form of loop, which is used to iterate over array or slice with key value pair.

Here in the example, we took an slice of string type then we used for with range keyword. There is two value will be return, first one as key of the slice and second one as the value on specific key in array/slice.
When we'll execute this code snippet will get following out put.