how can we check file existence?
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hi, i am writing my application(gui app) data to a text file (appdata.txt) and i want to make sure that every time when the application runs it doesn't create a new file or a copy of a file, the problem is:
1) how can i check if the appdata.txt already exists or not (if not then create new text file or else append data to existing one)
thanks for any help.
采纳的回答
Walter Roberson
2011-4-12
if exist('appdata.txt', 'file')
However, the bit about appending suggests that all you really need to do is,
fid = fopen('appdata.txt', 'at');
This will create a new file if needed and append to an existing file if it is there.
1 个评论
Jan
2011-4-12
EXIST(Name, 'file') replies a non-zero number for directories also:
if exist(tempdir, 'file'), disp('found'); end
A better check is:
if exist(Name, 'file') && ~exist(Name, 'dir')
or:
if exist(Name, 'file') == 2
I prefer "fopen(Name, 'r+')", because the append mode needs to locate the end of the file at first, which is time-consuming for large files.
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Yahia chs
2011-5-20
0 个投票
thank you very much this was really felpful!!!!!!!
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2011-4-12
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