在MATLAB中按值对JSON排序

qco9c6ql  于 2023-11-21  发布在  Matlab
关注(0)|答案(1)|浏览(145)

我想按“createdAt”对JSON文件中的值进行排序,并在plot函数中使用这些值。正如您所看到的,此列存储日期值,因此我已经转换了它。我已经应用了sort函数,但当我看到数据的输出时,似乎sort不适用。

data = loadjson('C:/data/default.json');
count_data = sum(cellfun(@(x) numel(x),data.Location)); %returns 21

for i=1:count_data
   createdAt= cellfun( @(cellElem) cellElem.createdAt, data.Location ,'UniformOutput',false);
   createdAtDate= datetime(createdAt(i),'InputFormat','dd-MM-yyyy HH:mm:ss','Format', 'dd-MM-yyyy n HH:mm:ss');
    [~,X] = sort(createdAtDate,'descend');
    out=data(X);
end

for i=1:count_data
  x = cellfun( @(cellElem) cellElem.createdAt, out.Location,'UniformOutput',false);
  disp(x);
 end

字符串
我的JSON文件:

"Location": [
{
  "id": "0b5965e5-c509-4522-a525-8ef5a49dadaf",
  "measureId": "5a6e9b79-dbb1-4482-acc1-d538f68ef01f",
  "locationX": 0.9039769252518151,
  "locationY": 0.2640594070404616,
  "createdAt": "06-01-2021 19:38:44"
},
{
  "id": "18714a2f-a8b3-4dc6-8a5b-114497fa9671",
  "measureId": "671f52bc-a066-494a-9dce-6e9ccfac6c1d",
  "locationX": 1.5592001730078755,
  "locationY": 0.5207689756815629,
  "createdAt": "06-01-2021 19:35:24"
},


先谢了。

n53p2ov0

n53p2ov01#

您需要提取所需的所有数据,然后进行排序

x = cellfun( @(cellElem) cellElem.locationX, data.Location );
y = cellfun( @(cellElem) cellElem.locationY, data.Location );
% Get date strings
d = cellfun( @(cellElem) cellElem.createdAt, data.Location, 'UniformOutput', false)
% Convert to datetime
d = datetime( d, 'InputFormat', 'dd-MM-yyyy HH:mm:ss' );
% Get the sort order
[~,idx] = sort( d );
% Sort other arrays
x = x(idx);
y = y(idx);

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另一种选择是使用表

x = cellfun( @(cellElem) cellElem.locationX, data.Location );
y = cellfun( @(cellElem) cellElem.locationY, data.Location );
% Get dates
d = cellfun( @(cellElem) cellElem.createdAt, data.Location, 'UniformOutput', false)
d = datetime( d, 'InputFormat', 'dd-MM-yyyy HH:mm:ss' );
% Create table
t = table( x(:), y(:), d(:), 'VariableNames', {'locationX','locationY','createdAt'} );
% Sortrows
t = sortrows( t, 'createdAt' );


在这里,您必须使用表而不是矩阵(尽管sortrows可以接受任何一种),因为跨列的数据类型是混合的。

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