How to get rid of zero value in a int slice in Go?
I am trying to find even numbers in a list of numbers, here is my attempt:
package main
import "fmt"
func main() {
nums := int{1, 2, 3, 4, 5, 6, 7}
res := int{}
for n := range nums {
if n%2 == 0 {
res = append(res, n)
}
}
fmt.Println(res)
}
It seems straightforward; however, when I run the program, I got the result
[0 2 4 6]
Where does the zero come from? It must be from the empty slice res. How can I get rid of this zero?
for-loop go slice
edited Nov 19 '18 at 12:50
icza
167k25333366
asked Nov 19 '18 at 12:43
NickNick
2,46942758
add a comment |
I am trying to find even numbers in a list of numbers, here is my attempt:
package main
import "fmt"
func main() {
nums := int{1, 2, 3, 4, 5, 6, 7}
res := int{}
for n := range nums {
if n%2 == 0 {
res = append(res, n)
}
}
fmt.Println(res)
}
It seems straightforward; however, when I run the program, I got the result
[0 2 4 6]
Where does the zero come from? It must be from the empty slice res. How can I get rid of this zero?
for-loop go slice
edited Nov 19 '18 at 12:50
icza
167k25333366
asked Nov 19 '18 at 12:43
NickNick
2,46942758
1
This is covered in the Tour of Go.
– Adrian
Nov 19 '18 at 14:14
add a comment |
I am trying to find even numbers in a list of numbers, here is my attempt:
package main
import "fmt"
func main() {
nums := int{1, 2, 3, 4, 5, 6, 7}
res := int{}
for n := range nums {
if n%2 == 0 {
res = append(res, n)
}
}
fmt.Println(res)
}
It seems straightforward; however, when I run the program, I got the result
[0 2 4 6]
Where does the zero come from? It must be from the empty slice res. How can I get rid of this zero?
for-loop go slice
edited Nov 19 '18 at 12:50
icza
167k25333366
asked Nov 19 '18 at 12:43
NickNick
2,46942758
I am trying to find even numbers in a list of numbers, here is my attempt:
package main
import "fmt"
func main() {
nums := int{1, 2, 3, 4, 5, 6, 7}
res := int{}
for n := range nums {
if n%2 == 0 {
res = append(res, n)
}
}
fmt.Println(res)
}
It seems straightforward; however, when I run the program, I got the result
[0 2 4 6]
Where does the zero come from? It must be from the empty slice res. How can I get rid of this zero?
for-loop go slice
for-loop go slice
edited Nov 19 '18 at 12:50
icza
167k25333366
asked Nov 19 '18 at 12:43
NickNick
2,46942758
edited Nov 19 '18 at 12:50
icza
167k25333366
asked Nov 19 '18 at 12:43
NickNick
2,46942758
edited Nov 19 '18 at 12:50
icza
167k25333366
edited Nov 19 '18 at 12:50
icza
167k25333366
edited Nov 19 '18 at 12:50
icza
167k25333366
167k25333366
asked Nov 19 '18 at 12:43
NickNick
2,46942758
asked Nov 19 '18 at 12:43
NickNick
2,46942758
asked Nov 19 '18 at 12:43
NickNick
2,46942758
2,46942758
1
This is covered in the Tour of Go.
– Adrian
Nov 19 '18 at 14:14
add a comment |
1
This is covered in the Tour of Go.
– Adrian
Nov 19 '18 at 14:14
1
1
This is covered in the Tour of Go.
– Adrian
Nov 19 '18 at 14:14
This is covered in the Tour of Go.
– Adrian
Nov 19 '18 at 14:14
add a comment |
1 Answer
1
active
oldest
votes
for n := range nums {
// ...
}
n is not the elements of the nums slice, it is the index. So basically you tested and added the indices of the elements to your res result slice.
Instead do this:
for _, n := range nums {
// ...
}
With this change, output will be (try it on the Go Playground):
[2 4 6]
This is detailed in Spec: For statements, For statements with range clause:
For each iteration, iteration values are produced as follows if the respective iteration variables are present:
Range expression 1st value 2nd value
array or slice a [n]E, *[n]E, or E index i int a[i] E
string s string type index i int see below rune
map m map[K]V key k K m[k] V
channel c chan E, <-chan E element e E
answered Nov 19 '18 at 12:45
iczaicza
167k25333366
add a comment |
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1 Answer
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active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
for n := range nums {
// ...
}
n is not the elements of the nums slice, it is the index. So basically you tested and added the indices of the elements to your res result slice.
Instead do this:
for _, n := range nums {
// ...
}
With this change, output will be (try it on the Go Playground):
[2 4 6]
This is detailed in Spec: For statements, For statements with range clause:
For each iteration, iteration values are produced as follows if the respective iteration variables are present:
Range expression 1st value 2nd value
array or slice a [n]E, *[n]E, or E index i int a[i] E
string s string type index i int see below rune
map m map[K]V key k K m[k] V
channel c chan E, <-chan E element e E
answered Nov 19 '18 at 12:45
iczaicza
167k25333366
add a comment |
for n := range nums {
// ...
}
n is not the elements of the nums slice, it is the index. So basically you tested and added the indices of the elements to your res result slice.
Instead do this:
for _, n := range nums {
// ...
}
With this change, output will be (try it on the Go Playground):
[2 4 6]
This is detailed in Spec: For statements, For statements with range clause:
For each iteration, iteration values are produced as follows if the respective iteration variables are present:
Range expression 1st value 2nd value
array or slice a [n]E, *[n]E, or E index i int a[i] E
string s string type index i int see below rune
map m map[K]V key k K m[k] V
channel c chan E, <-chan E element e E
answered Nov 19 '18 at 12:45
iczaicza
167k25333366
add a comment |
for n := range nums {
// ...
}
n is not the elements of the nums slice, it is the index. So basically you tested and added the indices of the elements to your res result slice.
Instead do this:
for _, n := range nums {
// ...
}
With this change, output will be (try it on the Go Playground):
[2 4 6]
This is detailed in Spec: For statements, For statements with range clause:
For each iteration, iteration values are produced as follows if the respective iteration variables are present:
Range expression 1st value 2nd value
array or slice a [n]E, *[n]E, or E index i int a[i] E
string s string type index i int see below rune
map m map[K]V key k K m[k] V
channel c chan E, <-chan E element e E
answered Nov 19 '18 at 12:45
iczaicza
167k25333366
for n := range nums {
// ...
}
n is not the elements of the nums slice, it is the index. So basically you tested and added the indices of the elements to your res result slice.
Instead do this:
for _, n := range nums {
// ...
}
With this change, output will be (try it on the Go Playground):
[2 4 6]
This is detailed in Spec: For statements, For statements with range clause:
For each iteration, iteration values are produced as follows if the respective iteration variables are present:
Range expression 1st value 2nd value
array or slice a [n]E, *[n]E, or E index i int a[i] E
string s string type index i int see below rune
map m map[K]V key k K m[k] V
channel c chan E, <-chan E element e E
answered Nov 19 '18 at 12:45
iczaicza
167k25333366
edited Nov 19 '18 at 17:35
answered Nov 19 '18 at 12:45
iczaicza
167k25333366
answered Nov 19 '18 at 12:45
iczaicza
167k25333366
answered Nov 19 '18 at 12:45
iczaicza
167k25333366
167k25333366
add a comment |
add a comment |
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1
This is covered in the Tour of Go.
– Adrian
Nov 19 '18 at 14:14