Explain the use of Go's built-in functions for common tasks?

Go provides a large number of built-in functions that perform common tasks and operations. Here are some examples:

**len()** - Returns the length of an array, slice, string, or map.

**append()** - Appends elements to a slice and returns the new slice.

**make()** - Creates a new slice, map, or channel.

**new()** - Allocates memory for a new value and returns a pointer to it.

**panic()** - Stops the normal flow of control and begins panicking, unwinding the stack until it reaches a recover statement or crashes the program.

**recover()** - Returns the value passed to panic and stops the panic.

**copy()** - Copies elements from one slice to another.

**delete()** - Deletes an element from a map.

**close()** - Closes a channel.

**cap()** - Returns the capacity of a slice or array.

These built-in functions can be very useful for performing common tasks in a concise and efficient way. For example, we can use **len()** to get the length of a slice:

mySlice := []int{1, 2, 3, 4}
length := len(mySlice)
fmt.Println(length) // prints 4

We can use **append()** to add elements to a slice:

mySlice := []int{1, 2, 3}
newSlice := append(mySlice, 4, 5)
fmt.Println(newSlice) // prints [1 2 3 4 5]

We can use **make()** to create a new slice:

mySlice := make([]int, 3, 5)
fmt.Println(mySlice) // prints [0 0 0]
fmt.Println(len(mySlice)) // prints 3
fmt.Println(cap(mySlice)) // prints 5

These are just a few examples of the many built-in functions that Go provides. By familiarizing ourselves with these functions and using them where appropriate, we can write more efficient and concise code.