[go-nuts] Re: why slice[len:len] okay, but slice[len] fail?
The other answers to your original question are reasonable, and probably
helpful. But I would also like to point out the definitive, though maybe
less helpful answer to both your original question, and this new one. You
see that behavior because the language specification says you should. Read
https://golang.org/ref/spec#Slice_expressions, particualrly the "Simple
slice expressions" section.
On Thursday, March 7, 2019 at 9:12:28 PM UTC-5, Halbert.Collier Liu wrote:
>
> Yes, i see,
> thank you so much!
>
> Could you please explain, why primes[6:6] okay, but primes[7:7] not?
> *:-)*
>
>
> 在 2019年3月7日星期四 UTC+8下午11:55:40，Robert Johnstone写道：
>>
>> Hello,
>>
>> When you use the colon, you taking a subset of the data. Further, the
>> notation is a closed/open. So a slice primes[6:6] is all of the element in
>> the array with index >= 6 and index < 6, which is an empty set. Note that
>> the type of the expression primes[6:6] is []int.
>>
>> When you don't use the colon, you are access a specific element. Since
>> the count is zero based, the valid indices are 0 through 5 inclusive. Note
>> that the type of the expression primes[6] is simply int.
>>
>> Good luck.
>>
>>
>> On Thursday, 7 March 2019 10:32:04 UTC-5, Halbert.Collier Liu wrote:
>>>
>>> Hi.
>>>
>>> The code like below:
>>>
>>> package main
>>>
>>> import "fmt"
>>>
>>> func main() {
>>> primes := [6]int{2, 3, 5, 7, 11, 13}
>>> fmt.Println(primes[6:6]) . // *OK*. return: []
>>> //fmt.Println(primes[6]) . // fail. out of bounds...
>>> }
>>>
>>> Why?
>>>
>>> Is the golang grammatical feature? or anything else..
>>>
>>> Any help, please!
>>>
>>
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Re: [go-nuts] Re: why slice[len:len] okay, but slice[len] fail?
Similar reason.
You might want to read about slices and arrays in go:
https://golang.org/doc/effective_go.html#slices
This might be helpful as well:
https://gobyexample.com/slices
On 3/8/19, Halbert.Collier Liu wrote:
> Yes, i see,
> thank you so much!
>
> Could you please explain, why primes[6:6] okay, but primes[7:7] not?
> *:-)*
>
>
> 在 2019年3月7日星期四 UTC+8下午11:55:40，Robert Johnstone写道：
>>
>> Hello,
>>
>> When you use the colon, you taking a subset of the data. Further, the
>> notation is a closed/open. So a slice primes[6:6] is all of the element
>> in
>> the array with index >= 6 and index < 6, which is an empty set. Note that
>>
>> the type of the expression primes[6:6] is []int.
>>
>> When you don't use the colon, you are access a specific element. Since
>> the count is zero based, the valid indices are 0 through 5 inclusive.
>> Note
>> that the type of the expression primes[6] is simply int.
>>
>> Good luck.
>>
>>
>> On Thursday, 7 March 2019 10:32:04 UTC-5, Halbert.Collier Liu wrote:
>>>
>>> Hi.
>>>
>>> The code like below:
>>>
>>> package main
>>>
>>> import "fmt"
>>>
>>> func main() {
>>> primes := [6]int{2, 3, 5, 7, 11, 13}
>>> fmt.Println(primes[6:6]) . // *OK*. return: []
>>> //fmt.Println(primes[6]) . // fail. out of bounds...
>>> }
>>>
>>> Why?
>>>
>>> Is the golang grammatical feature? or anything else..
>>>
>>> Any help, please!
>>>
>>
>
> --
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[go-nuts] Re: why slice[len:len] okay, but slice[len] fail?
Yes, i see,
thank you so much!
Could you please explain, why primes[6:6] okay, but primes[7:7] not? *:-)*
在 2019年3月7日星期四 UTC+8下午11:55:40，Robert Johnstone写道：
>
> Hello,
>
> When you use the colon, you taking a subset of the data. Further, the
> notation is a closed/open. So a slice primes[6:6] is all of the element in
> the array with index >= 6 and index < 6, which is an empty set. Note that
> the type of the expression primes[6:6] is []int.
>
> When you don't use the colon, you are access a specific element. Since
> the count is zero based, the valid indices are 0 through 5 inclusive. Note
> that the type of the expression primes[6] is simply int.
>
> Good luck.
>
>
> On Thursday, 7 March 2019 10:32:04 UTC-5, Halbert.Collier Liu wrote:
>>
>> Hi.
>>
>> The code like below:
>>
>> package main
>>
>> import "fmt"
>>
>> func main() {
>> primes := [6]int{2, 3, 5, 7, 11, 13}
>> fmt.Println(primes[6:6]) . // *OK*. return: []
>> //fmt.Println(primes[6]) . // fail. out of bounds...
>> }
>>
>> Why?
>>
>> Is the golang grammatical feature? or anything else..
>>
>> Any help, please!
>>
>
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[go-nuts] Re: why slice[len:len] okay, but slice[len] fail?
Hello,
When you use the colon, you taking a subset of the data. Further, the
notation is a closed/open. So a slice primes[6:6] is all of the element in
the array with index >= 6 and index < 6, which is an empty set. Note that
the type of the expression primes[6:6] is []int.
When you don't use the colon, you are access a specific element. Since the
count is zero based, the valid indices are 0 through 5 inclusive. Note
that the type of the expression primes[6] is simply int.
Good luck.
On Thursday, 7 March 2019 10:32:04 UTC-5, Halbert.Collier Liu wrote:
>
> Hi.
>
> The code like below:
>
> package main
>
> import "fmt"
>
> func main() {
> primes := [6]int{2, 3, 5, 7, 11, 13}
> fmt.Println(primes[6:6]) . // *OK*. return: []
> //fmt.Println(primes[6]) . // fail. out of bounds...
> }
>
> Why?
>
> Is the golang grammatical feature? or anything else..
>
> Any help, please!
>
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