package main
import (
"fmt"
)
func main(){
//float to int
fmt.Println(int64(1.9))
}
I got syntax error "Cannot convert expression of type 'float64' to type 'int64'", how to rectify it?
2 Answers
Type conversions have special rules for constants:
A constant value x can be converted to type T if x is representable by a value of T.
And even gives the following example:
int(1.2) // illegal: 1.2 cannot be represented as an int
If you really insist on truncating your float into an int, use a variable as an intermediary turning it into a non-constant conversion. Go will happily do the conversion and drop the fractional part, as mentioned further down in the spec:
When converting a floating-point number to an integer, the fraction is discarded (truncation towards zero).
So you can use the following:
package main
import (
"fmt"
)
func main() {
//float to int
f := 1.9
fmt.Println(int64(f))
}
Which outputs 1 as expected.
Or use one of the functions in the math package if you want finer control over rounding vs truncation.
constant 1.9 truncated to integerfmt.Println(math.Trunc(1.9))?