如何使用Matlab按字母顺序对属性-值对进行排序 [英] How to sort property -value pair in alphabetical order with Matlab

问题描述

我想向现有文件添加一个属性-值对.同时，所有属性应按字母顺序排序.例如:

I want to add a property-value pair to existing file. In the mean time all the properties should be ordered in alphabetical order. For example :

[Info] % property 1
value 1 
[system] % property 2
value 2

如何添加其他属性，以便所有属性均按字母顺序排序.我能够使用将属性-值对添加到文件的末尾 fh = fopen(filename,'a')，但我无法按字母顺序对它们进行排序.

How can i add additional property such that all properties will be sorted in alphabetical order. I was able to add property -value pair to the end of the file using fh = fopen(filename,'a') but i am not able to sort them alphabetically.

到目前为止，我尝试了以下操作，但是通过此操作，它仅打印新的property-value对.我想在打印新属性后再打印其余属性.

so far i tried this as follows but with this one it keeps printing only the new property-value pair . I want to print remaining properties onces it prints the new one.

function [] = myfun(filename ,propName,propvalue)
rfh = fopen(filename,'r');
tname = tempname();
wfh = fopen(tname,'w');
line = fgetl(rfh);

while ischar(line)

    if (line(1) == '[') && (line(end) == ']')
        property = lower(line(2:end-1)) % from ini file
        String2 = property;
        String1 = propName;
        [sat] = sor(String1,String2)% subfunction
        if sat == -1
            fprintf(wfh,'[%s]\r\n%s\r\n',propName,propvalue);
        else
            fprintf(wfh,'%s\r\n',line);
        end
    else
        fprintf(wfh,'%s\r\n',line);
    end
    line = fgetl(rfh);
end
fclose(rfh);
fclose(wfh);
movefile(tname,filename,'f')

function [sat] = sor(String1,String2)
Index = 1;

while Index < length(String1) && Index < length(String2) && String1(Index) == String2(Index)
    Index = Index + 1;
end

% Return the appropriate code
if String1(Index) < String2(Index)
    sat= -1
elseif String1(Index) > String2(Index)
    sat= +1
else % the characters at this position are equal -- the shorter of the two strings should be "less than"
    if length(String1) == length(String2)
        sat = 0
    elseif length(String1) <  length(String2)
        sat = -1
    else
        sat = +1
    end
end

推荐答案

如何将文件读入struct?

function fileData = readFileIntoStruct( fileName )
%
% read [property] value pairs file into struct
% 
fh = fopen( fileName, 'r' ); % read handle
line = fgetl( fh );
while ischar( line )
    % property
    tkn = regexp( line, '\[([^\]+)]\]', 'once', 'tokens' );
    % read next line for value
    val = fgetl( fh );
    fileDate.(tkn{1}) = val;
    line = fgetl( fh ); % keep reading
end
fclose( fh ); % don't forget to close the file at the end.

现在，您拥有的所有数据都为struct，其属性为fieldnames，值作为field值.

Now you have all the data as a struct with properties as fieldnames and values as the field value.

现在您可以通过以下方式简单地更新属性:

Now you can update a property simply by:

function fileData = updateProperty( fileData, propName, newVal )
if isfield( fileData, propName )
    fileData.(propName) = newVal;
else
    warning( 'property %s does not exist - please add it first', propName );
end

您可以添加属性:

function fileData = addProperty( fileData, propName, newVal )
if ~isfield( fileData, propName )
    fileData.(propName) = newVal;
else
    warning ( 'property %s already exists, use update to change its value', propName );
end

您可以使用 orderfields 按字母顺序对属性进行排序:

You can sort the properties alphabetically using orderfields:

fileData = orderfields( fileData );

您只需使用以下命令即可将struct写回到文件中:

You can write the struct back to file simply using:

function writeDataToFile( newFileName, fileData )
fopen( newFileName , 'w' ); %write handle
propNames = fieldnames( fileData );
for ii = 1:numel( propNames )
    fprintf( fh, '[%s]\r\n%s\r\n', propNames{ii}, fileData.(propNames{ii}) );
end
fclose( fh ); 

假设:

1. 属性名称是合法的Matlab字段名称(有关详细信息，请参见变量命名).

1. The properties' names are legitimate Matlab field names (see variable naming for details).

每个属性的值始终是一个字符串.

The value of each property is always a string.

在这些示例中，我没有包含任何错误检查代码(找不到文件，格式错误的字符串等)

I did not include any error-checking code in these examples (files not found, wrongly formatted strings, etc.)

我假设输入文件严格是"[prop] val"对，而没有任何其他注释等.

I assume the input file is strictly "[prop] val" pairs without any additional comments etc.

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