1

该程序的目标是在文件中查找一个字符串，并用该字符串所在的行吐出该字符串的所有实例。

我已经让它通过文件搜索并找到它们，只是无法将它们放入数组或让我存储所有它们的东西。现在它给了我最后一个实例，我可以轻松地在第 8 行和第 9 行之间插入一个中断来找到第一个实例。

如果有人知道如何存储有问题的字符串的每一行，那将是一个很大的帮助。

fid = fopen('....... file directory....')
prompt = 'What string are you searching for?  ';
str = input(prompt,'s');

i=0;
for j=1:10000;
tline = fgetl(fid);             %Returns next line of specified file
counter = counter + 1;          %Counts the next line
    if ischar(tline);           %Checks if the line is an array
    U=strfind(tline,str);       %Sets U to be 1 if strfind finds the string in line tline
        if isfinite(U) == 1                     
            what = tline;       %This is where I want to set the array positions equal to whatever tline is at that time, then move onto the next i and search for the next tline.
            i=i+1;
        end            
    end
end
4

2 回答 2

1

我建议如下：

haystack = 'test.txt';

prompt = 'What string are you searching for?  ';
needle = input(prompt, 's');

% MS Windows
if ispc

    output = regexp(evalc(['!find /N "' needle '" ' haystack]), char(10), 'split');

    output = regexp(output, '^\[([0-9].*)\]', 'tokens');
    output = cellfun(@(x)str2double(x{:}), output(~cellfun('isempty', output)))';

% OSX/Linux   
elseif isunix

    output = regexp(evalc(['!grep -n "' needle '" ' haystack]), char(10), 'split');

    output = regexp(output, '^([0-9].*):', 'tokens');    
    output = cellfun(@(x)str2double(x{:}), output(~cellfun('isempty', output)))';

% Anything else: stay in MATLAB
else

    fid = fopen(haystack);
    output = textscan(fid, '%s', 'delimiter', '\n');
    fclose(fid);

    output = find(~cellfun('isempty', regexp(output{1}, needle)));

end

内容test.txt：

garbage garbage garbage 
garbage garbage garbage 
garbage garbage garbage 
garbage garbage garbage 
garbage garbage garbage 
garbage valuable garbage 
garbage garbage garbage 
garbage garbage valuable 
garbage garbage garbage 
garbage garbage garbage 
garbage garbage garbage 
garbage garbage garbage 
garbage valuable garbage 
garbage garbage garbage 
garbage garbage garbage 
garbage garbage garbage

当我在 Windows 或 Linux 上执行代码或强制使用 MATLAB 版本时needle = 'valuable'，我得到正确的行号：

output = 
    6   
    8  
   13

使用特定于操作系统的工具的优点是它们的内存占用比纯 MATLAB 版本小得多（它们不会将整个文件加载到内存中）。即使您会在 MATLAB 中增加代码以防止这种情况发生（freadl例如通过使用循环），特定于操作系统的工具仍然会更快一些（并且对内存更友好）；这就是为什么我把它作为最后的手段:)

于 2013-07-10T07:02:46.340 回答
0

您可以将它们存储在结构数组中，例如：

lines = struct([]); % to store lines and line numbers    

idx = 1;

fid = fopen('somefile.txt');

tline = fgets(fid);

while ischar(tline)

    U=strfind(tline, str);

    if numel(U) > 0                            

        lines(end + 1).line = tline; % save line
        lines(end).lineNo = idx;     % save its number 
        lines(end).U = U;            % where is str in the just saved line            

    end

    tline = fgets(fid);

    idx = idx + 1;

end

fclose(fid);

lineTxts    = {lines(:).line};   % get lines in a cell
lineNumbers = [lines(:).lineNo]; % get line numbers as matrix
于 2013-07-10T00:48:24.887 回答