Documentation

dlmread

Read ASCII-delimited file of numeric data into matrix

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Syntax

M = dlmread(filename)
M = dlmread(filename,delimiter)
M = dlmread(filename,delimiter,R1,C1)
M = dlmread(filename,delimiter,[R1 C1 R2 C2])

Description

example

M = dlmread(filename)reads an ASCII-delimited numeric data file into matrixM. Thedlmreadfunction detects the delimiter from the file and treats repeated white spaces as a single delimiter.

M = dlmread(filename,delimiter)reads data from the file using the specified delimiter and treats repeated delimiter characters as separate delimiters.

example

M = dlmread(filename,delimiter,R1,C1)starts reading at row offsetR1and column offsetC1. For example, the offsetsR1=0,C1=0specify the first value in the file.

To specify row and column offsets without specifying a delimiter, use an empty character as a placeholder, for example,M = dlmread(filename,'',2,1).

example

M = dlmread(filename,delimiter,[R1C1R2C2])reads only the range bounded by row offsetsR1andR2and column offsetsC1andC2. Another way to define the range is to use spreadsheet notation, such as'A1..B7'instead of[0 0 6 1].

Examples

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Open Live Script

Read the sample file,count.dat.

M = dlmread('count.dat')
M =11 11 9 7 13 11 14 17 20 11 13 9 43 51 69 38 46 76 61 132 186 75 135 180 38 88 115 28 36 55

dlmreaddetects the delimiter from the file and returns a matrix.

Open Live Script

Write two matrices to a file, and then read the entire file usingdlmread.

Export a matrix to a file namedmyfile.txt. Then, append an additional matrix to the file that is offset one row below the first.

X = magic(3); dlmwrite('myfile.txt',[X*5 X/5],' ') dlmwrite('myfile.txt', X,'-append',...“roffset”,1,'delimiter',' ')

View the file contents.

typemyfile.txt
40 5 30 1.6 0.2 1.2 15 25 35 0.6 1 1.4 20 45 10 0.8 1.8 0.4 8 1 6 3 5 7 4 9 2

Read the entire file usingdlmread.

M = dlmread('myfile.txt')
M =40.0000 5.0000 30.0000 1.6000 0.2000 1.2000 15.0000 25.0000 35.0000 0.6000 1.0000 1.4000 20.0000 45.0000 10.0000 0.8000 1.8000 0.4000 8.0000 1.0000 6.0000 0 0 0 3.0000 5.0000 7.0000 0 0 0 4.0000 9.0000 2.0000 0 0 0

Whendlmreadimports a file containing nonrectangular data, it fills empty fields with zeros.

Create a file nameddlmlist.txtthat contains column headers and space-delimited values.

test max min direction 10 27.7 12.4 12 11 26.9 13.5 18 12 27.4 16.9 31 13 25.1 12.7 29

Read the numeric values in the file. Specify a space delimiter, a row offset of 1, and a column offset of 0.

文件名='dlmlist.txt'; M = dlmread(filename,' ',1,0)
M = 10.0000 27.7000 12.4000 12.0000 11.0000 26.9000 13.5000 18.0000 12.0000 27.4000 16.9000 31.0000 13.0000 25.1000 12.7000 29.0000

Create a file nameddlmlist.txtthat contains column headers and space-delimited values.

test max min direction 10 27.7 12.4 12 11 26.9 13.5 18 12 27.4 16.9 31 13 25.1 12.7 29

Read only the last two rows of numeric data from the file.

M = dlmread('dlmlist.txt',' ',[3 0 4 3])
M = 12.0000 27.4000 16.9000 31.0000 13.0000 25.1000 12.7000 29.0000

Input Arguments

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File name, specified as a character vector or string.

例子:'myFile.dat'or"myFile.dat"

Data Types:char|string

Field delimiter character, specified as a character vector or string. Use'\t'to specify a tab delimiter.

例子:','or","

例子:' 'or" "

Data Types:char|string

Starting row offset, specified as a nonnegative integer. The first row has an offset of 0.

Data Types:single|double|int8|int16|int32|int64|uint8|uint16|uint32|uint64

Starting column offset, specified as a nonnegative integer. The first column has an offset of 0.

Data Types:single|double|int8|int16|int32|int64|uint8|uint16|uint32|uint64

Ending row offset, specified as a nonnegative integer. The first row has an offset of 0.

Data Types:single|double|int8|int16|int32|int64|uint8|uint16|uint32|uint64

Ending column offset, specified as a nonnegative integer. The first column has an offset of 0.

Data Types:single|double|int8|int16|int32|int64|uint8|uint16|uint32|uint64

Tips

  • Skip header rows or columns by specifying row and column offsets. All values in the file other than headers must be numeric.

Algorithms

dlmreadfills empty delimited fields with zero. When thedlmreadfunction reads data files with lines that end with a nonspace delimiter, such as a semicolon, it returns a matrix,M, that has an additional last column of zeros.

dlmreadimports any complex number as a whole into a complex numeric field. This table shows valid forms for a complex number.

Form

Example

±±i|j

5.7-3.1i

±i|j

7 j

Embedded white space in a complex number is invalid anddlmreadregards it as a field delimiter.

See Also

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Topics

Introduced before R2006a

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