Diff a struct
in [Matlab]
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From: DLH on 5 Aug 2010 10:00 Is there a way (command/s) to diff a structure similar to diff'ing files on a unix/linux system? I have a several structures with dozens of fields, both strings & numbers, and I'd like a quick and simple way of findings which fields are different and what those differences are. Any suggestions? Thanks, dlh
From: Walter Roberson on 5 Aug 2010 10:50 DLH wrote: > Is there a way (command/s) to diff a structure similar to diff'ing files > on a unix/linux system? I have a several structures with dozens of > fields, both strings & numbers, and I'd like a quick and simple way of > findings which fields are different and what those differences are. Any > suggestions? No such routine is provided with Matlab (or at least I've never seen one.) A routine like this would not be all that difficult to write, but you would have to decide on a couple of things: - breadth first search, or depth first search? - if the field order is different but the same fields are there, then is this a "difference" that should be noted? - do you want something special to happen for class variables, since reading from such a variable can theoretically provoke an action ? - how do you want to handle class variables that have the same properties but have unique instance numbers? For example, A = handle(line(0,0)); B = handle(line(0,0)); Should "A" and "B" compare the same or different? - Case-sensitive string comparisons? Should it depend upon the variable? - is blank padding significant for strings? Leading or trailing? Or should trailing blanks not be significant for character arrays (since all the rows must be the same length and a difference in some other row might be forcing this row to be longer), or should trailing blanks be significant for character arrays if blanks are detected at the end of every row (which might imply deliberate allocation as a longer array) - should unicode 8764 ("mathematical tilde operator") compare the same as '~', should the unicode ellipsis character compare the same as '...', should unicode m-dash and n-dash compare the same; and so on for other strong glyph similarities? - has Walter confused you enough yet? -
From: DLH on 5 Aug 2010 11:44 Walter, Thanks for your response, and no you have not confused me yet. The points you raised are valid, and should be handled appropriately for a general algorithm. For my immediate purposes I merely want to perform a case-insensitive search, listing the differences in the fields common to both (or more) structures while ignoring whitespace. Field order is irrelevant, and although I expect all my structures to have the same fields the algorithm should detect and report any uncommon (extra or missing) fields. Thanks. __ dlh Walter Roberson <roberson(a)hushmail.com> wrote in message <YcA6o.1205$1v3.582(a)newsfe20.iad>... > DLH wrote: > > Is there a way (command/s) to diff a structure similar to diff'ing files > > on a unix/linux system? I have a several structures with dozens of > > fields, both strings & numbers, and I'd like a quick and simple way of > > findings which fields are different and what those differences are. Any > > suggestions? > > No such routine is provided with Matlab (or at least I've never seen one.) > > A routine like this would not be all that difficult to write, but you > would have to decide on a couple of things: > > - breadth first search, or depth first search? > > - if the field order is different but the same fields are there, then is > this a "difference" that should be noted? > > - do you want something special to happen for class variables, since > reading from such a variable can theoretically provoke an action ? > > - how do you want to handle class variables that have the same > properties but have unique instance numbers? For example, > > A = handle(line(0,0)); > B = handle(line(0,0)); > > Should "A" and "B" compare the same or different? > > - Case-sensitive string comparisons? Should it depend upon the variable? > > - is blank padding significant for strings? Leading or trailing? Or > should trailing blanks not be significant for character arrays (since > all the rows must be the same length and a difference in some other row > might be forcing this row to be longer), or should trailing blanks be > significant for character arrays if blanks are detected at the end of > every row (which might imply deliberate allocation as a longer array) > > - should unicode 8764 ("mathematical tilde operator") compare the same > as '~', should the unicode ellipsis character compare the same as '...', > should unicode m-dash and n-dash compare the same; and so on for other > strong glyph similarities? > > - has Walter confused you enough yet? > > -
From: Oleg Komarov on 5 Aug 2010 13:32 "DLH " <nospam(a)nospam.com> wrote in message <i3em84$jme$1(a)fred.mathworks.com>... > Walter, > > Thanks for your response, and no you have not confused me yet. > > The points you raised are valid, and should be handled appropriately for a general algorithm. For my immediate purposes I merely want to perform a case-insensitive search, listing the differences in the fields common to both (or more) structures while ignoring whitespace. Field order is irrelevant, and although I expect all my structures to have the same fields the algorithm should detect and report any uncommon (extra or missing) fields. > > Thanks. > __ > dlh > > Walter Roberson <roberson(a)hushmail.com> wrote in message <YcA6o.1205$1v3.582(a)newsfe20.iad>... > > DLH wrote: > > > Is there a way (command/s) to diff a structure similar to diff'ing files > > > on a unix/linux system? I have a several structures with dozens of > > > fields, both strings & numbers, and I'd like a quick and simple way of > > > findings which fields are different and what those differences are. Any > > > suggestions? > > > > No such routine is provided with Matlab (or at least I've never seen one.) > > > > A routine like this would not be all that difficult to write, but you > > would have to decide on a couple of things: > > > > - breadth first search, or depth first search? > > > > - if the field order is different but the same fields are there, then is > > this a "difference" that should be noted? > > > > - do you want something special to happen for class variables, since > > reading from such a variable can theoretically provoke an action ? > > > > - how do you want to handle class variables that have the same > > properties but have unique instance numbers? For example, > > > > A = handle(line(0,0)); > > B = handle(line(0,0)); > > > > Should "A" and "B" compare the same or different? > > > > - Case-sensitive string comparisons? Should it depend upon the variable? > > > > - is blank padding significant for strings? Leading or trailing? Or > > should trailing blanks not be significant for character arrays (since > > all the rows must be the same length and a difference in some other row > > might be forcing this row to be longer), or should trailing blanks be > > significant for character arrays if blanks are detected at the end of > > every row (which might imply deliberate allocation as a longer array) > > > > - should unicode 8764 ("mathematical tilde operator") compare the same > > as '~', should the unicode ellipsis character compare the same as '...', > > should unicode m-dash and n-dash compare the same; and so on for other > > strong glyph similarities? > > > > - has Walter confused you enough yet? > > > > - A hint: help fieldnames help strcmpi Oleg
From: Bruno Luong on 5 Aug 2010 14:17
"DLH " <nospam(a)nospam.com> wrote in message <i3em84$jme$1(a)fred.mathworks.com>... > Walter, > > Thanks for your response, and no you have not confused me yet. > > The points you raised are valid, and should be handled appropriately for a general algorithm. For my immediate purposes I merely want to perform a case-insensitive search, listing the differences in the fields common to both (or more) structures while ignoring whitespace. Field order is irrelevant, and although I expect all my structures to have the same fields the algorithm should detect and report any uncommon (extra or missing) fields. > > Thanks. There is ambiguity if you decide to ignore fieldname case. If the same structure have two fields that differ by case, which one should be compared? There is no sense to allow such thing. Otherwise here is a short function to compare structures (with case-sensitive then): function strucdiff(s1, s2, s1str, s2str) % Calling syntax: >> strucdiff(s1, s2) if nargin<=2 s1str = inputname(1); s2str = inputname(2); end if isstruct(s1) && isstruct(s2) f1 = fieldnames(s1); f2 = fieldnames(s2); g1 = setdiff(f2,f1); for k=1:length(g1) fprintf('<%s.%s> is missing.\n', s1str, g1{k}); end g2 = setdiff(f1,f2); for k=1:length(g2) fprintf('<%s.%s> is missing.\n', s2str, g2{k}); end fcommon = intersect(f1,f2); for k=1:length(fcommon) fk = fcommon{k}; strucdiff(s1.(fk), s2.(fk), ... [s1str '.' fk], [s2str '.' fk]) end elseif ~isstruct(s1) && isstruct(s2) fprintf('<%s> is not struct but <%s> is.\n', s1str, s2str); elseif isstruct(s1) && ~isstruct(s2) fprintf('<%s> is struct but <%s> is not.\n', s1str, s2str); elseif ~isequal(s1, s2) fprintf('<%s> and <%s> differs.\n', s1str, s2str); end end % Bruno |