Best way to sort array data.
in [TCL]
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From: Donald Arseneau on 12 Apr 2010 03:33 On Apr 11, 10:33 pm, Glenn Jackman <gle...(a)ncf.ca> wrote: > At 2010-04-11 11:52PM, "tom.rmadilo" wrote: > > > On Apr 11, 8:23 pm, Keith <kilowattra...(a)use-reply-to.invalid> wrote: > [...] > > > I want to sort the values in the arrays. > > > > $foo(arr,1) = "C wordone" > > > $foo(arr,2) = "A wordone" > > > I assume once you sort, you end up with a list. So ditch the array and > > use a list to begin with like this: > > > % set mylist {{arr,1 "C wordone"} {arr,2 "A wordone"}} > > Well, you don't have to ditch the array: > > set mylist [list] > foreach {key value} [array get foo] { > lappend mylist [list $key $value] > } > > > then use [lsort] > > > % lsort -index 1 $mylist > > {arr,2 "A wordone"} {arr,1 "C wordone"} > > If you have Tcl 8.6, you can achieve the same kind of thing quicker: > > array set foo {arr,1 "C wordone" arr,2 "A wordone"} > lsort -stride 2 -index 1 [array get foo] > # ==> arr,2 {A wordone} arr,1 {C wordone} > > -- > Glenn Jackman > Write a wise saying and your name will live forever. -- Anonymous
From: Donald Arseneau on 12 Apr 2010 04:05 On Apr 11, 10:33 pm, Glenn Jackman <gle...(a)ncf.ca> wrote: > array set foo {arr,1 "C wordone" arr,2 "A wordone"} > lsort -stride 2 -index 1 [array get foo] > # ==> arr,2 {A wordone} arr,1 {C wordone} I don't think that is useful, especially if it is converted back to an array. I imagine Keith wants # ==> arr,1 {A wordone} arr,2 {C wordone} Since the list of names emitted by [array get] is unsorted, any sorting work is really cumbersome, and indicates the choice of data structure was poor. The data should be in nested lists rather than in a pseudo- multidemensional array. Working with the array as specified entails sorting both the names and the values separately, and is made more cumbersome by the lack of an [array values] command. (Even [dict values] doesn't allow selecting a subset of keys directly, but I will use dict anyway.) set foodict [array get foo "arr,*"] foreach name [lsort -dictionary [dict keys $foodict]] \ value [lsort -however [dict values $foodict]] { set foo($name) $value } Keith never said *how* the values are to be sorted (strings, numbers, whatever) so I used "-however" for the sort order. Donald
From: Glenn Jackman on 12 Apr 2010 10:14 At 2010-04-12 04:05AM, "Donald Arseneau" wrote: > On Apr 11, 10:33�pm, Glenn Jackman <gle...(a)ncf.ca> wrote: > > � � array set foo {arr,1 "C wordone" arr,2 "A wordone"} > > � � lsort -stride 2 -index 1 [array get foo] > > � � # ==> arr,2 {A wordone} arr,1 {C wordone} > > I don't think that is useful, especially if it is converted back to an > array. > I imagine Keith wants > > # ==> arr,1 {A wordone} arr,2 {C wordone} Well, we're all imagining what Keith wants ("I want to sort the values in the arrays.") -- Glenn Jackman Write a wise saying and your name will live forever. -- Anonymous
From: tom.rmadilo on 12 Apr 2010 12:05 On Apr 12, 7:14 am, Glenn Jackman <gle...(a)ncf.ca> wrote: > Well, we're all imagining what Keith wants ("I want to sort the values > in the arrays.") In Tcl you don't sort arrays, you sort lists. Tcl Arrays do not have an ordered representation, they just have an interface. Another problem with sorting on values is that the values could be the same, so the actual order of the un-ordered values will affect result of the sort. If the data is stored as an array before being dumped into a list, you will not be able to predict the results of the sort. Predictable results can be produced using two [lsort]s: % set mylist {{a b} {b b} {e b} {d b} {h b} {aa b}} % set sorted [lsort -index 0 [lsort -index 1 $mylist]] {a b} {aa b} {b b} {d b} {e b} {h b} This doesn't work: % set not-sorted [lsort -index 1 $mylist] {a b} {b b} {e b} {d b} {h b} {aa b} This works: % set still-sorted [lsort -index 0 [lsort -index 1 [lreverse $mylist]]] {a b} {aa b} {b b} {d b} {e b} {h b}
From: MSEdit on 13 Apr 2010 03:37
Is there something wrong with foreach ent [lsort -dictionary [array names foo]] { # Process the entries in order $foo($ent) } or am I missing something ? this is what I always use. Martyn |