[go-nuts] How to initialize two dimension array

[Yang Yang]

Hi, All

I'm new to Go programming language. I want to initialize a two
dimension array.
But I cannot find how to do it in the document.
Is there a way to initialize [3][3]int in declaration.

Best regards

Yang

[Daniel Smith]

This should work:

ia := [3][3]int{[3]int{1,2,3},[3]int{1,2,3},[3]int{1,2,3}}

--
Daniel Smith
http://www.schaumburggoclub.org/

[Yang Yang]

Thanks. However, it looks not very elegant.
IMHO, If Go provides matlab-like array initialization, it will be better.

For example:

ia := [3][3]int{{1,2,3},{1,2,3},{1,2,3}}

Best regards

Yang

2010/5/4 Daniel Smith <luken...@gmail.com>

[peterGo]

Yang,

Has this already been discussed?

a slice of slices
http://groups.google.com/group/golang-nuts/browse_thread/thread/0b1b4bb1085988fd/598f3ae6051c2a7b

Peter

On May 4, 12:40 pm, Yang Yang <comety...@gmail.com> wrote:
> Thanks. However, it looks not very elegant.
> IMHO, If Go provides matlab-like array initialization, it will be better.
> For example:
> ia := [3][3]int{{1,2,3},{1,2,3},{1,2,3}}
>
> Best regards
>
> Yang
>

> 2010/5/4 Daniel Smith <lukenin...@gmail.com>

>
> > This should work:
>
> > ia := [3][3]int{[3]int{1,2,3},[3]int{1,2,3},[3]int{1,2,3}}
>

[Kyle Consalus]

On Tue, May 4, 2010 at 9:40 AM, Yang Yang <come...@gmail.com> wrote:

Thanks. However, it looks not very elegant.
IMHO, If Go provides matlab-like array initialization, it will be better.

For example:

ia := [3][3]int{{1,2,3},{1,2,3},{1,2,3}}

golang.org/doc/go_programming_faq.html#nested_array_verbose 

[hotei]

Yang,

In my (admittedly short) experience go often provides a way that works
and ... nothing else. If Daniel says that's the way it's done then
it's unlikely there's another way. This is a feature not a bug. It's
one of the reasons you can't take a breath, much less drink a cup of
tea while your program compiles. Personally I'll take this trade-off
and pass up elegance. In most cases (especially mine) elegance had
come to mean "comfortable", ie. like the language I used before. In a
month or so I expect to find go "comfortable" and the problem kind of
just goes away... (no pun intended) (really!) :-)

Hotei

On May 4, 12:40 pm, Yang Yang <comety...@gmail.com> wrote:

> Thanks. However, it looks not very elegant.
> IMHO, If Go provides matlab-like array initialization, it will be better.
> For example:
> ia := [3][3]int{{1,2,3},{1,2,3},{1,2,3}}
>
> Best regards
>
> Yang
>

> 2010/5/4 Daniel Smith <lukenin...@gmail.com>

>
>
>
>
>
> > This should work:
>
> > ia := [3][3]int{[3]int{1,2,3},[3]int{1,2,3},[3]int{1,2,3}}
>

[Steven]

On Tue, May 4, 2010 at 1:31 PM, hotei <ravens...@cox.net> wrote:

Yang,

In my (admittedly short) experience go often provides a way that works
and ...  nothing else.  If Daniel says that's the way it's done then
it's unlikely there's another way.  This is a feature not a bug.  It's
one of the reasons you can't take a breath, much less drink a cup of
tea while your program compiles.  Personally I'll take this trade-off
and pass up elegance.   In most cases (especially mine) elegance had
come to mean "comfortable", ie. like the language I used before.  In a
month or so I expect to find go "comfortable" and the problem kind of
just goes away... (no pun intended)  (really!)  :-)

Hotei

For the official answer on this, see: http://golang.org/doc/go_programming_faq.html#nested_array_verbose

I highly recommend reading the language spec, effective go, and the various FAQ. They answer a lot of these types of questions. 

[Stanley Steel]

From the aforementioned link:

"Some of Go's designers had worked on other languages that derived types automatically in such expressions, but the special cases that arise can be messy, especially when interfaces, nil, constant conversions, and such are involved. It seemed better to require the full type information. That way there will be no surprises."


What is an example of a special case?  I don't understand what the problem could be and why it needs to be so verbose.

[Russ Cox]

> What is an example of a special case?

Being able to shorten

var x = [][]int{[]int{1,2,3}}

to

var x = [][]int{{1,2,3}}

but not being able to shorten

var x = []interface{}{[]int{1,2,3}}

to

var x = []interface{}{{1,2,3}}

Russ

[Norman Yarvin]

I can see not wanting to special-case 'int', but what about
special-casing 'interface'? For static types, once the type is defined
by the outer array declaration, it is easily inferred for the inner ones,
which seems to leave interfaces as the only exceptional case. The
exception seems like it'd be a natural one: when initializing a dynamic
type, one naturally needs to say what static type it contains.


--
Norman Yarvin http://yarchive.net

[alexand...@gmail.com]

func Pic(dx, dy int) [][]uint8 {

pic := make([][]uint8, dy)

for i := 0; i < dy; i++ {

pic[i] = make([]uint8, dx)

for j := 0; j < dx; j++ {

pic[i][j] = uint8(float64(i)*math.Log(float64(j)))

}

}

return pic

}

在 2010年5月5日星期三 UTC+8上午12:30:56，Yang Yang写道：

[Seb Binet]

On Thu, Aug 18, 2016 at 9:32 AM, <alexand...@gmail.com> wrote:

func Pic(dx, dy int) [][]uint8 {

pic := make([][]uint8, dy)

for i := 0; i < dy; i++ {

pic[i] = make([]uint8, dx)

for j := 0; j < dx; j++ {

pic[i][j] = uint8(float64(i)*math.Log(float64(j)))

}

}

return pic

}

[][]uint8 is not an array: it's a slice of slices.

OP asked for a 3x3 array.

one can create such a beast like that:

 https://play.golang.org/p/n0warBR7Pn

 

hth,

-s

在 2010年5月5日星期三 UTC+8上午12:30:56，Yang Yang写道：

Hi, All

I'm new to Go programming language. I want to initialize a two
dimension array.
But I cannot find how to do it in the document.
Is there a way to initialize [3][3]int in declaration.

Best regards

Yang

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[asit dhal]

Here is a link to initialize a static array

http://www.dotnetperls.com/2d-go

And at runtime,

https://rosettacode.org/wiki/Create_a_two-dimensional_array_at_runtime#Go

Warm Regards,

Asit Dhal

http://bit.ly/193ASIT

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