Count Unique Occurrences of Elements

Question

Patrick Rungrugeecharoen 2019-5-26

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/464041-count-unique-occurrences-of-elements

评论： Patrick Rungrugeecharoen 2019-5-27

I have the following vectors:

Stops = [w w x x x y z ] %String
Buses = [A B C A C D B] % String
UniqueBuses = [A B C D] %String

I would like to have an output which tells me that:

Stop w has 1 A, 1 B.
Stop x has 2 C, 1 A.
Stop y has 1 D.
Stotp z has 1B.

Any help would be appreciated thank you!

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

per isakson 2019-5-26

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/464041-count-unique-occurrences-of-elements#answer_376653

编辑：per isakson 2019-5-26

在 MATLAB Online 中打开

Try this

%%
Stops = [ "w", "w", "x", "x", "x", "y", "z" ];   % String
Buses = [ "A", "B", "C", "A", "C", "D", "B" ];   % String
UniqueBuses = [ "A", "B", "C", "D" ];            % String
%%
UniqueStops = unique( Stops );
for stop = UniqueStops
    ism = ismember( Stops, stop );
    stopping_buses = Buses( ism );
    str = compose( "Stop %s has", stop );
    for bus = UniqueBuses
        num = sum( double( ismember( stopping_buses, bus ) ) );
        if num >= 1
            str = compose( "%s %d %s,", str, num, bus );
        end
    end
    disp( str )
end

it outputs

Stop w has 1 A, 1 B,
Stop x has 1 A, 2 C,
Stop y has 1 D,
Stop z has 1 B,
>> 

3 个评论
显示 1更早的评论隐藏 1更早的评论

per isakson 2019-5-26

编辑：per isakson 2019-5-26

Questions

Stops, Buses and UniqueBuses are all of them rows, i.e not columns?
Are you comfortable with Matlabs debugging tools? If not see Debug a MATLAB Program

Proposal

Set Pause on Errors
Run the script with your larger dataset
When the execution halts before throwing the error inspect the values of str, num, bus. Does their dimensions agree? They shall all be <1x1>

Patrick Rungrugeecharoen 2019-5-26

To answer your question:

The Stops, Buses and UniqueBuses are all vector columns actually. (Not familiar with MATLAB vector notation - sorry for the confusion).

The str, num and bus dimensions do not agree:

str is a 1994 x 1 string.
num is a 1 x 1 double.
bus is a 251 x 1 string.

My larger data set was (if that helps):

Stop is 5632 x 1 string.
Buses is a 5632 x 1 string.
UniqueBuses is a 251 x 1 string.
UniqueStops is a 1994 x 1 string.

If it helps the output can just be a matrix form instead of string form?

请先登录，再进行评论。

Answer 2

per isakson 2019-5-26

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/464041-count-unique-occurrences-of-elements#answer_376662

编辑：per isakson 2019-5-26

在 MATLAB Online 中打开

I cannot make comments, thus I use an Answer

To ensure that Stops, Buses and UniqueBuses are row vectors add the following lines in the top of the script

Stops = reshape( Stops, 1,[] );
Buses = reshape( Buses, 1,[] );
UniqueBuses = reshape( UniqueBuses, 1,[] );

"If it helps the output can just be a matrix form instead of string form?" Not needed. These reshape() statements should solve the problem. They output row vectors for both row and column vectors.

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Patrick Rungrugeecharoen 2019-5-27

Thank you very much it works now.

Out of curiosity how would the code look if I wanted a header row consisting of UniqueBuses and the leading column to have UniqueStops then the matrix filled out with a bunch of numbers based on these results?

请先登录，再进行评论。