MATLAB的数据导入与导出.ppt

1、MATLAB的数据导入与导出,MATLAB的数据导入,数据的直接输入 A=1 2 3 4 5 6； M文件中生成 利用fopen，fread，和MATLAB输入输出函数。 从ASCII文件中导入 利用load命令,LOAD 接受绝对或相对路径输入。如果文件的扩展名不是.mat，则系统把文件当作ASCII码文件进行处理。 单独使用时，默认输入的命令matlab.mat。如果找不到这个文件，则会报错。 LOAD FILENAME X loads only X. LOAD FILENAME X Y Z . loads just the specified variables. The wildcar

2、d * loads variables that match a pattern (MAT-file only). 如果文件是mat文件，所需变量将在工作空间产生，否则，会产生一个双精度矩阵，矩阵名为文件名。 S = LOAD(.) returns the contents of FILENAME in variable S. If FILENAME is a MAT file, S is a struct containing fields matching the variables retrieved. If FILENAME is an ASCII file, S is a doubl

3、e precision array.,举例,load fname a* % Load variables starting with a load fname -regexp bd3$ % Load variables starting with b and % followed by 3 digits load fname -regexp d % Load variables containing any digits,利用特定文件读取函数 dlmread wk1read textscan textread 创建mex文件读取文件 创建其他程序文件读取,MATLAB的数据导出,diary s

4、ave ascii 以特定格式写入文件 利用特定文件写入程序 dlmwrite 作为mat文件输出数据,MATLAB的文件操作,UIGETFILE 对话框打开文件方式. FILENAME, PATHNAME, FILTERINDEX = UIGETFILE(FILTERSPEC, TITLE) 显示一个需要用户完成的对话框，返回文件名，文件路径，和是否打开成功，如果打开成功，返回成功标志，否则会出现一错误信息，用户可以打开另一文件，或取消。 filename, pathname, filterindex = uigetfile(*.m, Pick an M-file);,MATLAB的文件操作

5、,UIPUTFILE 对话框打开文件方式. FILENAME, PATHNAME, FILTERINDEX = UIPUTFILE(FILTERSPEC, TITLE) 显示一个需要用户完成的对话框，返回文件名，文件路径，和是否打开成功，如果打开成功，返回成功标志，否则会出现一错误信息，用户可以打开另一文件，或取消。 filename, pathname = uiputfile(matlab.mat, Save Workspace as);,MATLAB的文件操作,FOPEN 打开文件 FILENAME 可以是一个相对路径，如果文件不在当前目录，系统将会在其他路径进行搜索。 FID = FOP

6、EN(FILENAME,PERMISSION) FID 称为文件标识符，如果错误，返回-1,MATLAB的文件操作,r read w write (create if necessary) a append (create if necessary) r+ read and write (do not create) w+ truncate or create for read and write a+ read and append (create if necessary) W write without automatic flushing A append without automa

7、tic flushing,MATLAB的文件操作,Two file identifiers are automatically available and need not be opened. They are FID=1 (standard output) and FID=2 (standard error). FID, MESSAGE = FOPEN(FILENAME,PERMISSION) returns a system dependent error message if the open is not successful.,MATLAB的文件操作,FCLOSE Close fi

8、le. ST = FCLOSE(FID) closes the file with file identifier FID, which is an integer obtained from an earlier FOPEN. FCLOSE returns 0 if successful and -1 if not. ST = FCLOSE(a) closes all open files, except 0, 1 and 2.,MATLAB的文件操作,FGETS Read line from file, keep newline character. TLINE = FGETS(FID)

9、returns the next line of a file associated with file identifier FID as a MATLAB string. The line terminator is included. Use FGETL to get the next line WITHOUT the line terminator. If just an end-of-file is encountered then -1 is returned.,MATLAB的文件操作,FPRINTF Write formatted data to file. COUNT = FP

10、RINTF(FID,FORMAT,A,.) formats the data in the real part of array A (and in any additional array arguments), under control of the specified FORMAT string, and writes it to the file associated with file identifier FID. COUNT is the number of bytes successfully written. FID is an integer file identifier obtained from FOPEN. It can also be 1 for standard output (the screen) or 2 for standard error. If FID is omitted