* Merging two lua tables
@ 2022-08-29 12:20 Aditya Mahajan via ntg-context
2022-08-29 12:29 ` Aditya Mahajan via ntg-context
2022-08-29 14:28 ` Hans Hagen via ntg-context
0 siblings, 2 replies; 8+ messages in thread
From: Aditya Mahajan via ntg-context @ 2022-08-29 12:20 UTC (permalink / raw)
To: mailing list for ConTeXt users; +Cc: Aditya Mahajan
Hi,
How do I merge two lua tables? I believe that table.merge or table.merged should do the trick, but I cannot figure out how to use them.
```
local t1 = { 1, 2 }
local t2 = { 8, 9 }
local m1 = {}
table.merge(m1,t1, t2)
table.print(m1)
local m2 = table.merged(t1, t2)
table.print(m2)
```
Processing the file with context filename shows that both m1 and m2 are {8, 9}. What am I missing.
Thanks,
Aditya
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* Re: Merging two lua tables
2022-08-29 12:20 Merging two lua tables Aditya Mahajan via ntg-context
@ 2022-08-29 12:29 ` Aditya Mahajan via ntg-context
2022-08-29 17:33 ` BPJ via ntg-context
2022-08-29 14:28 ` Hans Hagen via ntg-context
1 sibling, 1 reply; 8+ messages in thread
From: Aditya Mahajan via ntg-context @ 2022-08-29 12:29 UTC (permalink / raw)
To: Aditya Mahajan via ntg-context; +Cc: Aditya Mahajan
On Mon, 29 Aug 2022, Aditya Mahajan via ntg-context wrote:
> Hi,
>
> How do I merge two lua tables? I believe that table.merge or table.merged should do the trick, but I cannot figure out how to use them.
>
> ```
> local t1 = { 1, 2 }
> local t2 = { 8, 9 }
>
> local m1 = {}
> table.merge(m1,t1, t2)
> table.print(m1)
>
> local m2 = table.merged(t1, t2)
> table.print(m2)
> ```
>
> Processing the file with context filename shows that both m1 and m2 are {8, 9}. What am I missing.
Looking at the code, I see what is happening. table.merge(d) assume that the tables are key-value tables so the keys of the first table are silently overwritten by the send. I guess, I'll have to write my own function to merge "array" tables.
Aditya
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* Re: Merging two lua tables
2022-08-29 12:20 Merging two lua tables Aditya Mahajan via ntg-context
2022-08-29 12:29 ` Aditya Mahajan via ntg-context
@ 2022-08-29 14:28 ` Hans Hagen via ntg-context
2022-08-30 5:52 ` Aditya Mahajan via ntg-context
1 sibling, 1 reply; 8+ messages in thread
From: Hans Hagen via ntg-context @ 2022-08-29 14:28 UTC (permalink / raw)
To: ntg-context; +Cc: Hans Hagen
On 8/29/2022 2:20 PM, Aditya Mahajan via ntg-context wrote:
> Hi,
>
> How do I merge two lua tables? I believe that table.merge or table.merged should do the trick, but I cannot figure out how to use them.
>
> ```
> local t1 = { 1, 2 }
> local t2 = { 8, 9 }
>
> local m1 = {}
> table.merge(m1,t1, t2)
> table.print(m1)
>
> local m2 = table.merged(t1, t2)
> table.print(m2)
> ```
>
> Processing the file with context filename shows that both m1 and m2 are {8, 9}. What am I missing.
table.imerge(m1,t1, t2)
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
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wiki : https://contextgarden.net
___________________________________________________________________________________
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Merging two lua tables
2022-08-29 12:29 ` Aditya Mahajan via ntg-context
@ 2022-08-29 17:33 ` BPJ via ntg-context
2022-08-29 18:10 ` Hans Hagen via ntg-context
0 siblings, 1 reply; 8+ messages in thread
From: BPJ via ntg-context @ 2022-08-29 17:33 UTC (permalink / raw)
To: mailing list for ConTeXt users; +Cc: BPJ
[-- Attachment #1.1: Type: text/plain, Size: 1961 bytes --]
Hi,
I use the attached Lua function to merge array, map and mixed tables alike
(but differently! :-) The trick is to check if each key is numeric or not,
append if it is and overwrite if it isn't.
This function just ignores non-table arguments because that is what I
usually want. You may want to throw an error instead. Also it uses
table.pack. You might need to use `tab = {...}` and ipairs, or implement
pack:
``````lua
local function pack (...)
return { n = select('#', ...), ... }
end
``````
Den mån 29 aug. 2022 14:32Aditya Mahajan via ntg-context <ntg-context@ntg.nl>
skrev:
> On Mon, 29 Aug 2022, Aditya Mahajan via ntg-context wrote:
>
> > Hi,
> >
> > How do I merge two lua tables? I believe that table.merge or
> table.merged should do the trick, but I cannot figure out how to use them.
> >
> > ```
> > local t1 = { 1, 2 }
> > local t2 = { 8, 9 }
> >
> > local m1 = {}
> > table.merge(m1,t1, t2)
> > table.print(m1)
> >
> > local m2 = table.merged(t1, t2)
> > table.print(m2)
> > ```
> >
> > Processing the file with context filename shows that both m1 and m2 are
> {8, 9}. What am I missing.
>
> Looking at the code, I see what is happening. table.merge(d) assume that
> the tables are key-value tables so the keys of the first table are silently
> overwritten by the send. I guess, I'll have to write my own function to
> merge "array" tables.
>
> Aditya
>
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to
> the Wiki!
>
> maillist : ntg-context@ntg.nl /
> https://www.ntg.nl/mailman/listinfo/ntg-context
> webpage : https://www.pragma-ade.nl / http://context.aanhet.net
> archive : https://bitbucket.org/phg/context-mirror/commits/
> wiki : https://contextgarden.net
>
> ___________________________________________________________________________________
>
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[-- Attachment #2: table-merge.lua --]
[-- Type: application/octet-stream, Size: 679 bytes --]
local function merge_tables (...)
tab = table.pack(...)
rv = {}
for i=1,tab.n do
-- Is it a table? Ignore if not!
if 'table' == type(tab[i]) then
for k,v in pairs(tab[i]) do
-- Is the key a number?
if 'number' == type(k) then
-- Append it!
rv[#rv+1] = v
else
-- Non-numeric key: overwrite value
rv[k] = v
end
end
end
end
return rv
end
dump = require"pl.pretty".dump
tab_a = {
'a', 'b', 'c',
foo = 'A',
bar = 'B',
baz = 'C',
}
tab_b = {
'd', 'e', 'f',
baz = 'D',
bop = 'E',
fop = 'F',
}
merged = merge_tables(tab_a, 'quux', tab_b, 0.0)
dump(merged)
[-- Attachment #3: Type: text/plain, Size: 496 bytes --]
___________________________________________________________________________________
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Merging two lua tables
2022-08-29 17:33 ` BPJ via ntg-context
@ 2022-08-29 18:10 ` Hans Hagen via ntg-context
2022-08-30 8:56 ` BPJ via ntg-context
0 siblings, 1 reply; 8+ messages in thread
From: Hans Hagen via ntg-context @ 2022-08-29 18:10 UTC (permalink / raw)
To: ntg-context; +Cc: Hans Hagen
On 8/29/2022 7:33 PM, BPJ via ntg-context wrote:
> Hi,
>
> I use the attached Lua function to merge array, map and mixed tables alike
> (but differently! :-) The trick is to check if each key is numeric or not,
> append if it is and overwrite if it isn't.
you really want something like this then:
local tab = table.pack(...)
local rv = {}
> This function just ignores non-table arguments because that is what I
> usually want. You may want to throw an error instead. Also it uses
> table.pack. You might need to use `tab = {...}` and ipairs, or implement
> pack:
I might add table.himerged (hash and index) but slightly different (and
some 30% faster) to util-tab but i think merging mixed hash/indexed
tables is rare.
Hans
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
webpage : https://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Merging two lua tables
2022-08-29 14:28 ` Hans Hagen via ntg-context
@ 2022-08-30 5:52 ` Aditya Mahajan via ntg-context
0 siblings, 0 replies; 8+ messages in thread
From: Aditya Mahajan via ntg-context @ 2022-08-30 5:52 UTC (permalink / raw)
To: Hans Hagen via ntg-context; +Cc: Aditya Mahajan
On Mon, 29 Aug 2022, Hans Hagen via ntg-context wrote:
> On 8/29/2022 2:20 PM, Aditya Mahajan via ntg-context wrote:
> > Hi,
> >
> > How do I merge two lua tables? I believe that table.merge or table.merged
> should do the trick, but I cannot figure out how to use them.
> >
> > ```
> > local t1 = { 1, 2 }
> > local t2 = { 8, 9 }
> >
> > local m1 = {}
> > table.merge(m1,t1, t2)
> > table.print(m1)
> >
> > local m2 = table.merged(t1, t2)
> > table.print(m2)
> > ```
> >
> > Processing the file with context filename shows that both m1 and m2 are {8,
> 9}. What am I missing.
> table.imerge(m1,t1, t2)
Ah, thanks!
Aditya
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Merging two lua tables
2022-08-29 18:10 ` Hans Hagen via ntg-context
@ 2022-08-30 8:56 ` BPJ via ntg-context
2022-08-30 10:08 ` BPJ via ntg-context
0 siblings, 1 reply; 8+ messages in thread
From: BPJ via ntg-context @ 2022-08-30 8:56 UTC (permalink / raw)
To: mailing list for ConTeXt users; +Cc: BPJ
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Den mån 29 aug. 2022 20:13Hans Hagen via ntg-context <ntg-context@ntg.nl>
skrev:
> On 8/29/2022 7:33 PM, BPJ via ntg-context wrote:
> > Hi,
> >
> > I use the attached Lua function to merge array, map and mixed tables
> alike
> > (but differently! :-) The trick is to check if each key is numeric or
> not,
> > append if it is and overwrite if it isn't.
>
> you really want something like this then:
>
> local tab = table.pack(...)
> local rv = {}
>
Thanks. I was manually translating from MoonScript (https://moonscript.org)
where variables are local by default.
> > This function just ignores non-table arguments because that is what I
> > usually want. You may want to throw an error instead. Also it uses
> > table.pack. You might need to use `tab = {...}` and ipairs, or implement
> > pack:
> I might add table.himerged (hash and index) but slightly different (and
> some 30% faster) to util-tab but i think merging mixed hash/indexed
> tables is rare.
>
> Hans
>
> -----------------------------------------------------------------
> Hans Hagen | PRAGMA ADE
> Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
> tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
> -----------------------------------------------------------------
>
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to
> the Wiki!
>
> maillist : ntg-context@ntg.nl /
> https://www.ntg.nl/mailman/listinfo/ntg-context
> webpage : https://www.pragma-ade.nl / http://context.aanhet.net
> archive : https://bitbucket.org/phg/context-mirror/commits/
> wiki : https://contextgarden.net
>
> ___________________________________________________________________________________
>
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___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________
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* Re: Merging two lua tables
2022-08-30 8:56 ` BPJ via ntg-context
@ 2022-08-30 10:08 ` BPJ via ntg-context
0 siblings, 0 replies; 8+ messages in thread
From: BPJ via ntg-context @ 2022-08-30 10:08 UTC (permalink / raw)
To: bpj; +Cc: BPJ, mailing list for ConTeXt users
[-- Attachment #1.1: Type: text/plain, Size: 2194 bytes --]
Come to think of it you may also want to check that numeric indices are
indeed positive integers before appending their value. I usually don't
because their not being so is rare.
Den tis 30 aug. 2022 10:56BPJ <bpj@melroch.se> skrev:
>
>
> Den mån 29 aug. 2022 20:13Hans Hagen via ntg-context <ntg-context@ntg.nl>
> skrev:
>
>> On 8/29/2022 7:33 PM, BPJ via ntg-context wrote:
>> > Hi,
>> >
>> > I use the attached Lua function to merge array, map and mixed tables
>> alike
>> > (but differently! :-) The trick is to check if each key is numeric or
>> not,
>> > append if it is and overwrite if it isn't.
>>
>> you really want something like this then:
>>
>> local tab = table.pack(...)
>> local rv = {}
>>
>
> Thanks. I was manually translating from MoonScript (https://moonscript.org)
> where variables are local by default.
>
>
>> > This function just ignores non-table arguments because that is what I
>> > usually want. You may want to throw an error instead. Also it uses
>> > table.pack. You might need to use `tab = {...}` and ipairs, or implement
>> > pack:
>> I might add table.himerged (hash and index) but slightly different (and
>> some 30% faster) to util-tab but i think merging mixed hash/indexed
>> tables is rare.
>>
>> Hans
>>
>> -----------------------------------------------------------------
>> Hans Hagen | PRAGMA ADE
>> Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
>> tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
>> -----------------------------------------------------------------
>>
>> ___________________________________________________________________________________
>> If your question is of interest to others as well, please add an entry to
>> the Wiki!
>>
>> maillist : ntg-context@ntg.nl /
>> https://www.ntg.nl/mailman/listinfo/ntg-context
>> webpage : https://www.pragma-ade.nl / http://context.aanhet.net
>> archive : https://bitbucket.org/phg/context-mirror/commits/
>> wiki : https://contextgarden.net
>>
>> ___________________________________________________________________________________
>>
>
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___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
webpage : https://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : https://contextgarden.net
___________________________________________________________________________________
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2022-08-29 12:20 Merging two lua tables Aditya Mahajan via ntg-context
2022-08-29 12:29 ` Aditya Mahajan via ntg-context
2022-08-29 17:33 ` BPJ via ntg-context
2022-08-29 18:10 ` Hans Hagen via ntg-context
2022-08-30 8:56 ` BPJ via ntg-context
2022-08-30 10:08 ` BPJ via ntg-context
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