how can we check file existence?
조회 수: 21 (최근 30일)
이전 댓글 표시
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.
댓글 수: 0
채택된 답변
Walter Roberson
2011년 4월 12일
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.
댓글 수: 1
Jan
2011년 4월 12일
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.
추가 답변 (2개)
참고 항목
카테고리
Help Center 및 File Exchange에서 Environment and Settings에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!