如何在Matlab中打开DBase文件（.DBF）？
 

我已经通过Matlab Central进行了搜索和搜索，但是找不到任何直接在Matlab中打开DBF文件的方法。在TMW File Exchange中有一些对DBFREAD函数的引用，但现在不再可用。真的有问题吗？

我确实有数据库工具箱，但是在那里找不到dbf支持。

我不想使用Excel或其他工具在Matlab之外转换文件，因为我有很多文件要处理。 ODBC也不是很好，我也需要代码在Mac和Unix下工作。

请帮忙。



[B]回答：[/B]

我联系了DBFREAD函数的作者Brian Madsen，该函数已从File Exchange中删除，可能是因为The Mathworks将在将来的某些发行版中将该函数包含在MATLAB中。 Brian允许我在这里发布此功能。所有版权信息均保持不变。我只修改了第33-38行，以允许DBFREAD读取工作目录之外的文件。

function [dbfData, dbfFieldNames] = dbfread(filename, records2read, requestedFieldNames) %DBFREAD Read the specified records and fields from a DBF file. % % [DATA, NAMES] = DBFREAD(FILE) reads numeric, float, character and date % data and field names from a DBF file, FILE. % % [DATA, NAMES] = DBFREAD(FILE, RECORDS2READ) reads only the record % numbers specified in RECORDS2READ, a scalar or vector. % % [DATA, NAMES] = DBFREAD(FILE, RECORDS2READ, REQUESTEDFIELDNAMES) reads % the data from the fields, REQUESTEDFIELDNAMES, for the specified % records. REQUESTEDFIELDNAMES must be a cell array. The fields in the % output will follow the order given in REQUESTEDFIELDNAMES. % % Examples: % % % Get all records and a list of the field names from a DBF file. % [DATA,NAMES] = dbfread('c:\matlab\work\mydbf') % % % Get data from records 3:5 and 10 from a DBF file. % DATA = dbfread('c:\matlab\work\mydbf',[3:5,10]) % % % Get data from records 1:10 for three of the fields in a DBF file. % DATA = dbfread('c:\matlab\work\mydbf',1:10,{'FIELD1' 'FIELD3' 'FIELD5'}) % % See also XLSREAD, DLMREAD, DLMWRITE, LOAD, FILEFORMATS, TEXTSCAN. % Copyright 2008 The MathWorks, Inc. % $Revision: 1.0 $ $Date: 2008/04/18 05:58:17 $ [pathstr,name,ext] = fileparts(filename); dbfFileId = fopen(filename,'r','ieee-le'); if (dbfFileId == -1) dbfFileId = fopen(fullfile(pathstr, [name '.dbf']),'r','ieee-le'); end if (dbfFileId == -1) dbfFileId = fopen(fullfile(pathstr, [name '.DBF']),'r','ieee-le'); end if (dbfFileId == -1) eid = sprintf('MATLAB:%s:missingDBF', mfilename); msg = sprintf('Failed to open file %s.dbf or file %s.DBF.',... name, name); error(eid,'%s',msg) end info = dbfinfo(dbfFileId); if ~exist('requestedFieldNames','var') dbfFieldNames = {info.FieldInfo.Name}; requestedFieldNames = dbfFieldNames; else dbfFieldNames = (info.FieldInfo(matchFieldNames(info,requestedFieldNames)).Name); end fields2read = matchFieldNames(info,requestedFieldNames); % The first byte in each record is a deletion indicator lengthOfDeletionIndicator = 1; if ~exist('records2read','var') records2read = (1:info.NumRecords); elseif max(records2read) > info.NumRecords eid = sprintf('MATLAB:%s:invalidRecordNumber', mfilename); msg = sprintf('Record number %d does not exist, please select from the range 1:%d.',... max(records2read), info.NumRecords); error(eid,'%s',msg) end % Loop over the requested fields, reading in the data dbfData = cell(numel(records2read),numel(fields2read)); for k = 1:numel(fields2read), n = fields2read(k); fieldOffset = info.HeaderLength ... + sum([info.FieldInfo(1:(n-1)).Length]) ... + lengthOfDeletionIndicator; fseek(dbfFileId,fieldOffset,'bof'); formatString = sprintf('%d*uint8=>char',info.FieldInfo(n).Length); skip = info.RecordLength - info.FieldInfo(n).Length; data = fread(dbfFileId,[info.FieldInfo(n).Length info.NumRecords],formatString,skip); dbfData(:,k) = feval(info.FieldInfo(n).ConvFunc,(data(:,records2read)')); % dbfData(:,k) = info.FieldInfo(n).ConvFunc(data(:,records2read)'); end fclose(dbfFileId); %-------------------------------------------------------------------------- function fields2read = matchFieldNames(info, requestedFieldNames) % Determine which fields to read. allFieldNames = {info.FieldInfo.Name}; if isempty(requestedFieldNames) if ~iscell(requestedFieldNames) % Default case: User omitted the parameter, return all fields. fields2read = 1:info.NumFields; else % User supplied '{}', skip all fields. fields2read = []; end else % Match up field names to see which to return. fields2read = []; for k = 1:numel(requestedFieldNames) index = strmatch(requestedFieldNames{k},allFieldNames,'exact'); if isempty(index) wid = sprintf('MATLAB:%s:nonexistentDBFName',mfilename); wrn = sprintf('DBF name ''%s'' %s\n%s',requestedFieldNames{k},... 'doesn''t match an existing DBF name.',... ' It will be ignored.'); warning(wid,wrn) end for l = 1:numel(index) % Take them all in case of duplicate names. fields2read(end+1) = index(l); end end end %-------------------------------------------------------------------------- function info = dbfinfo(fid) %DBFINFO Read header information from DBF file. % FID File identifier for an open DBF file. % INFO is a structure with the following fields: % Filename Char array containing the name of the file that was read % DBFVersion Number specifying the file format version % FileModDate A string containing the modification date of the file % NumRecords A number specifying the number of records in the table % NumFields A number specifying the number of fields in the table % FieldInfo A 1-by-numFields structure array with fields: % Name A string containing the field name % Type A string containing the field type % ConvFunc A function handle to convert from DBF to MATLAB type % Length A number of bytes in the field % HeaderLength A number specifying length of the file header in bytes % RecordLength A number specifying length of each record in bytes % Copyright 1996-2005 The MathWorks, Inc. % $Revision: 1.1.10.4 $ $Date: 2005/11/15 01:07:13 $ [version, date, numRecords, headerLength, recordLength] = readFileInfo(fid); fieldInfo = getFieldInfo(fid); info.Filename = fopen(fid); info.DBFVersion = version; info.FileModDate = date; info.NumRecords = numRecords; info.NumFields = length(fieldInfo); info.FieldInfo = fieldInfo; info.HeaderLength = headerLength; info.RecordLength = recordLength; %---------------------------------------------------------------------------- function [version, date, numRecords, headerLength, recordLength] = readFileInfo(fid) % Read from File Header. fseek(fid,0,'bof'); version = fread(fid,1,'uint8'); year = fread(fid,1,'uint8') + 1900; month = fread(fid,1,'uint8'); day = fread(fid,1,'uint8'); dateVector = datevec(sprintf('%d/%d/%d',month,day,year)); dateForm = 1;% dd-mmm-yyyy date = datestr(dateVector,dateForm); numRecords = fread(fid,1,'uint32'); headerLength = fread(fid,1,'uint16'); recordLength = fread(fid,1,'uint16'); %---------------------------------------------------------------------------- function fieldInfo = getFieldInfo(fid) % Form FieldInfo by reading Field Descriptor Array. % % FieldInfo is a 1-by-numFields structure array with the following fields: % Name A string containing the field name % Type A string containing the field type % ConvFunc A function handle to convert from DBF to MATLAB type % Length A number equal to the length of the field in bytes lengthOfLeadingBlock = 32; lengthOfDescriptorBlock = 32; lengthOfTerminator = 1; fieldNameOffset = 16; % Within table field descriptor fieldNameLength = 11; % Get number of fields. fseek(fid,8,'bof'); headerLength = fread(fid,1,'uint16'); numFields = (headerLength - lengthOfLeadingBlock - lengthOfTerminator)... / lengthOfDescriptorBlock; % Read field lengths. fseek(fid,lengthOfLeadingBlock + fieldNameOffset,'bof'); lengths = fread(fid,[1 numFields],'uint8',lengthOfDescriptorBlock - 1); % Read the field names. fseek(fid,lengthOfLeadingBlock,'bof'); data = fread(fid,[fieldNameLength numFields],... sprintf('%d*uint8=>char',fieldNameLength),... lengthOfDescriptorBlock - fieldNameLength); data(data == 0) = ' '; % Replace nulls with blanks names = cellstr(data')'; % Read field types. fseek(fid,lengthOfLeadingBlock + fieldNameLength,'bof'); dbftypes = fread(fid,[numFields 1],'uint8=>char',lengthOfDescriptorBlock - 1); % Convert DBF field types to MATLAB types. typeConv = dbftype2matlab(upper(dbftypes)); % Return a struct array. fieldInfo = cell2struct(... [names; {typeConv.MATLABType}; {typeConv.ConvFunc}; num2cell(lengths)],... {'Name', 'Type', 'ConvFunc', 'Length'},1)'; %---------------------------------------------------------------------------- function typeConv = dbftype2matlab(dbftypes) % Construct struct array with MATLAB types & conversion function handles. typeLUT = ... {'N', 'double', @str2double2cell;... % DBF numeric 'F', 'double', @str2double2cell;... % DBF float 'C', 'char', @cellstr;... % DBF character 'D', 'char', @cellstr}; % DBF date unsupported = struct('MATLABType', 'unsupported', ... 'ConvFunc', @cellstr); % Unsupported types: Logical,Memo,N/ANameVariable,Binary,General,Picture numFields = length(dbftypes); if numFields ~= 0 typeConv(numFields) = struct('MATLABType',[],'ConvFunc',[]); end for k = 1:numFields idx = strmatch(dbftypes(k),typeLUT(:,1)); if ~isempty(idx) typeConv(k).MATLABType = typeLUT{idx,2}; typeConv(k).ConvFunc = typeLUT{idx,3}; else typeConv(k) = unsupported; end end %---------------------------------------------------------------------------- function out = str2double2cell(in) % Translate IN, an M-by-N array of class char, to an M-by-1 column vector % OUT, of class double. IN may be blank- or null-padded. If IN(k,:) does % not represent a valid scalar value, then OUT(k) has value NaN. if isempty(in) out = {[NaN]}; return end % Use sprintf when possible, but fall back to str2double for unusual cases. fmt = sprintf('%%%df',size(in,2)); [data count] = sscanf(reshape(in',[1 numel(in)]),fmt); if count == size(in,1) out = cell(count,1); for k = 1:count out{k} = data(k); end else out = num2cell(str2double(cellstr(in))); end [B]更新[/B]

如果输入参数中的位数不同，则STR2DOUBLE2CELL子功能有时会无法正常工作（请参阅[URL="http://www.mathworks.com/matlabcentral/newsreader/view_thread/289593"]此讨论[/URL] ）。

这是我的STR2DOUBLE2CELL版本：

function out = str2double2cell(in) % Translate IN, an M-by-N array of class char, to an M-by-1 column vector % OUT, of class double. IN may be blank- or null-padded. If IN(k,:) does % not represent a valid scalar value, then OUT(k) has value NaN. if isempty(in) out = {[NaN]}; return end out = cellfun(@str2double,cellstr(in),'UniformOutput',false);

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