Flash cards
Review the key moves
What is the main idea behind Go For Loops?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___; statement2; statement3 {Put the learning moves in the order that makes the concept easiest to apply.
The for loop loops through a block of code a specified number of times.
The for loop is the only loop available in Go.
Go for Loop
Loops are handy if you want to run the same code over and over again, each time with a different value.
Each execution of a loop is called an iteration .
The for loop can take up to three statements:
Syntax
for
statement1; statement2; statement3 {
// code to be executed for each iteration
}statement1 Initializes the loop counter value.
statement2 Evaluated for each loop iteration. If it evaluates to TRUE, the loop continues. If it evaluates to FALSE, the loop ends.
statement3 Increases the loop counter value.
Note
These statements don't need to be present as loops arguments. However, they need to be present in the code in some form.
The continue Statement
The continue statement is used to skip one or more iterations in the loop. It then continues with the next iteration in the loop.
Example
package main
import ("fmt")
func main() {
for i:=0; i < 5; i++ {
if i == 3 {
continue
}
fmt.Println(i)
}
}The break Statement
The break statement is used to break/terminate the loop execution.
Example
package main
import ("fmt")
func main() {
for i:=0; i < 5; i++ {
if i == 3 {
break
}
fmt.Println(i)
}
}Note
continue and break are usually used with conditions .
Nested Loops
It is possible to place a loop inside another loop.
Here, the "inner loop" will be executed one time for each iteration of the "outer loop":
Example
package main
import ("fmt")
func main() {
adj := [2]string{"big", "tasty"}
fruits := [3]string{"apple", "orange", "banana"}
for i:=0; i < len(adj); i++ {
for j:=0; j < len(fruits); j++ {
fmt.Println(adj[i],fruits[j])
}
}
}The Range Keyword
The range keyword is used to more easily iterate through the elements of an array, slice or map. It returns both the index and the value.
The range keyword is used like this:
Syntax
for
index, value := range
array
| slice
| map {
// code to be executed for each iteration
}rangeTip
To only show the value or the index, you can omit the other output using an underscore ( _ ).
idxidx