finding min and max values from a file
3 次查看(过去 30 天)
显示 更早的评论
In a text file, I have a pressure listed. I am combining several files and I would like my program to find the highest pressure and lowest pressure. I think I use line=getl, but do not know how to format the line correctly, can you help me out?
Thank you!
0 个评论
回答(2 个)
Fangjun Jiang
2011-6-17
Please provide an example of your text file so we can help you. The task sounds not that hard. There are plenty of similar QAs regarding import text file for data. Once you get all the data, use min() and max() will get you the result.
Fangjun Jiang
2011-6-18
Thank you for showing the example. I saw you posted similar questions a few times. Not sure how representative are these text files to your real data files. Your problem is trivial. The data format in your text file is irregular. You need to read the file and do specific string processing to get the data you want. I wrote the function below just show it can be done. But I suspect that it won't apply to your real data files. I hope you can use it as a starting point to get your task done.
Copy the following line to create ParseText.m file thus create the ParseText() function.
function [PR,FX,FY]=ParseText(TextFile)
fid=fopen(TextFile,'rt');
while ~feof(fid)
TextLine=fgetl(fid);
if strfind(TextLine,'Pressure:')
PR=textscan(TextLine,'%s%f%s');
PR=PR{2};
continue;
end
if strfind(TextLine,'FX:')
TextLine=strrep(TextLine,'FX:','');
FX=textscan(TextLine,'%f','delimiter',',');
FX=FX{1};
continue;
end
if strfind(TextLine,'FY:')
TextLine=strrep(TextLine,'FY:','');
FY=textscan(TextLine,'%s','delimiter',',');
FY=FY{1};
continue;
end
disp('Un-recognized text line.');
end
fclose(fid);
Then run the following lines, assume you have the three text files as shown in your comment.
>> [PR.PR1,FX.FX1,FY.FY1]=ParseText('File_20psi.txt');
>> [PR.PR2,FX.FX2,FY.FY2]=ParseText('File_30psi.txt');
>> [PR.PR3,FX.FX3,FY.FY3]=ParseText('File_40psi.txt');
>> Pressure=[PR.PR1,PR.PR2,PR.PR3]
Pressure =
20 30 40
>> FX_ALL=[FX.FX1;FX.FX2;FX.FX3]'
FX_ALL =
1 2 3 4 5 6 7 8 9
>> FY_ALL=[FY.FY1;FY.FY2;FY.FY3]'
FY_ALL =
'a' 'b' 'c' 'd' 'e' 'f'
>> max(Pressure)
ans =
40
>> min(Pressure)
ans =
20
7 个评论
Fangjun Jiang
2011-6-20
Like Walter suggested, the code is for a M-function. You need to call it with an input argument 'File_20psi.txt', which is the name of the text file. The variable TextFile in the code will then has 'File_20psi.txt' as its value.
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Data Import and Export 的更多信息
产品
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!