Sort a variables in structure

I have this kind of variables in a struct:

var_1
var_10
var_11
...
    var_19
var_2
var_21

and so on until var_24

Is there a manner to sort them like

var_1
var_2
var_3
var_4
...
var_24

?

Answer 1

[Davide Masiello]

See example below

clear,clc

s.var_1 = 1;
s.var_6 = 1;
s.var_3 = 1;
s.var_2 = 1;
s.var_5 = 1;
s.var_4 = 1;

s

s = struct with fields:
    var_1: 1
    var_6: 1
    var_3: 1
    var_2: 1
    var_5: 1
    var_4: 1

orderfields(s)

ans = struct with fields:
    var_1: 1
    var_2: 1
    var_3: 1
    var_4: 1
    var_5: 1
    var_6: 1

Answer 2

[Stephen23]

Rather than forcing pseudo-indices into fieldnames, why not use an array with indexing (e.g. a cell array) ?

Here are two ways to sort those fieldnames into alphanumeric order:

S0.var_1  = 101;
S0.var_10 = 110;
S0.var_11 = 111;
S0.var_19 = 119;
S0.var_2  = 102;
S0.var_21 = 121

S0 = struct with fields:
     var_1: 101
    var_10: 110
    var_11: 111
    var_19: 119
     var_2: 102
    var_21: 121

Method 1: REGEXP and SORT (only sorts the numeric part):

[~,X] = sort(str2double(regexp(fieldnames(S0),'\d+$','match','once')));
S1 = orderfields(S0,X)

S1 = struct with fields:
     var_1: 101
     var_2: 102
    var_10: 110
    var_11: 111
    var_19: 119
    var_21: 121

Method two: NATSORT (must be downloaded first, provides a full alphanumeric sort):

[~,X] = natsort(fieldnames(S0));
S2 = orderfields(S0,X)

S2 = struct with fields:
     var_1: 101
     var_2: 102
    var_10: 110
    var_11: 111
    var_19: 119
    var_21: 121