Numbers as dictionary keys

[Ernie Rael]

In vim9.txt there's

The key type can be string, number, bool or float.  Other types result in an
error.  A number can be given with and without the []:

Don't know if the following shows a bug in implementation or documentation.
The two dictionaries are not equal.

    vim9script

    var d1 = {[000123]: 'foo'}
    echo d1
    ### output {'123': 'foo'}

    var d2 = {000123: 'foo'}
    echo d2
    ### output {'000123': 'foo'}

    if d1 == d2
        echo 'EQUAL'
    else
        echo 'NOT EQUAL'
    endif

[Bram Moolenaar]

This is correct. The key eventually is always a string. If you use a
number and convert it to a string then leading zeros are dropped. If
you use a string with leading zeros, they are kept. This is in the help
below ":he E717".

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[Ernie Rael]

On 4/28/22 7:27 AM, Bram Moolenaar wrote:
> Ernie Rael wrote:
>
>> In vim9.txt there's
>>
>> The key type can be string, number, bool or float.  Other types result in an
>> error.  A number can be given with and without the []:
>>
>> Don't know if the following shows a bug in implementation or documentation.
>> The two dictionaries are not equal.
>>
>>     vim9script
>>
>>     var d1 = {[000123]: 'foo'}
>>     echo d1
>>     ### output {'123': 'foo'}
>>
>>     var d2 = {000123: 'foo'}
>>     echo d2
>>     ### output {'000123': 'foo'}
>>
>>     if d1 == d2
>>         echo 'EQUAL'
>>     else
>>         echo 'NOT EQUAL'
>>     endif
> This is correct. The key eventually is always a string. If you use a
> number and convert it to a string then leading zeros are dropped. If
> you use a string with leading zeros, they are kept. This is in the help
> below ":he E717".
>

E717 says

You can use a Number, it will be converted
...Note that the String '04' and the Number 04 are different,
since the Number will be converted to the String '4'.

According to that, in the example I started with, {000123: 'foo'}, the
number should be converted. But it is not being converted. Try

vim9script
echo {000123: 'foo'}

-ernie

[Bram Moolenaar]

Ernie Rael wrote:

> >> In vim9.txt there's
> >>

> >> The key type can be string, number, bool or float.  Other types res> ult in an

That is not a number but a string. As you noticed before, using [expr]
does use 000123 as a number, then converts it to a string.
Using the {key: value} syntax the "key" part is always a string.

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[Ernie Rael]

Isn't this doc in vim9.txt wrong (or at least highly misleading)

The key type can be string, number, bool or float.  Other types

result in an

error.  A number can be given with and without the []: >

    var dict = {123: 'without', [456]: 'with'}
    echo dict
    {'456': 'with', '123': 'without'}

It is not the same "with and without"

At E717, where it is talking about "Dictionary creation", it says
"Number will be converted to String". But that might be a legacy script
thing and so out of my experience.

-ernie

[Bram Moolenaar]

Ernie Rael wrote:

> >>>> In vim9.txt there's
> >>>>

> >>>> The key type can be string, number, bool or float.=C2=A0 Other types r=
> es> ult in an
> >>>> error.=C2=A0 A number can be given with and without the []:
> >>>>
> >>>> Don't know if the following shows a bug in implementation or documenta=

> ti> on.
> >>>> The two dictionaries are not equal.
> >>>>

> >>>> =C2=A0=C2=A0=C2=A0 vim9script
> >>>>
> >>>> =C2=A0=C2=A0=C2=A0 var d1 =3D {[000123]: 'foo'}
> >>>> =C2=A0=C2=A0=C2=A0 echo d1
> >>>> =C2=A0=C2=A0=C2=A0 ### output {'123': 'foo'}
> >>>>
> >>>> =C2=A0=C2=A0=C2=A0 var d2 =3D {000123: 'foo'}
> >>>> =C2=A0=C2=A0=C2=A0 echo d2
> >>>> =C2=A0=C2=A0=C2=A0 ### output {'000123': 'foo'}
> >>>>
> >>>> =C2=A0=C2=A0=C2=A0 if d1 =3D=3D d2
> >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 echo 'EQUAL'
> >>>> =C2=A0=C2=A0=C2=A0 else
> >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 echo 'NOT EQUAL'
> >>>> =C2=A0=C2=A0=C2=A0 endif

> >>> This is correct. The key eventually is always a string. If you use a
> >>> number and convert it to a string then leading zeros are dropped. If

> >>> you use a string with leading zeros, they are kept. This is in the hel=

This should be clearer:

The key type can be string, number, bool or float. Other types result in an

error. Without using [] the value is used as a string, keeping leading zeros.
An expression given with [] is evaluated and then converted to a string.
Leading zeros will then be dropped: >
var dict = {000123: 'without', [000456]: 'with'}
echo dict
{'456': 'with', '000123': 'without'}

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