Textscan - reading data into Cell Array

I have a time stamped text file that looks like this

 1 1 POSITION -3.4310 2.9600 2.0200 0.3250 0.2440 0.2300

and it is repeated 10000 times with some text and blank lines in between, like shown below

2 1 POSITION -3.4310 2.9600 2.0200 0.3250 0.2440 0.2300

asdasdsd

fasdasdasdasdasdsad

3 1 POSITION -3.4310 2.9600 2.0200 0.3250 0.2440 0.2300

4 1 POSITION -3.4310 2.9600 2.0200 0.3250 0.2440 0.2300

I am using the following textscan statement to read the data above

pos= textscan(fid, '%f%f%s%10.3f%10.3f%10.3f%10.3f%10.3f%10.3f', 1, 'headerLines', 1)

 Can anyone tell me how to read one line of data using textscan and then ignore couple of lines after that and then using textscan again to read another line and then append to the existing cell array?

Thanks in advance,

Sridhar

Answer 1

[Fangjun Jiang]

To read a line, use Line=fgetl(fid). textscan works on string Line too.

[sridhar]

I need to parse the text input into different fields ( cant do it using fgetl...very slow)

[Fangjun Jiang]

Those irregular text, do they have particular patterns? Can you utilize the 'CommentStyle' parameter of textscan()?

Also, why use %10.3f instead of %f?

[Fangjun Jiang]

Line='1 1 POSITION -3.4310 2.9600 2.0200 0.3250 0.2440 0.2300';

pos= textscan(Line, '%f%f%s%10.3f%10.3f%10.3f%10.3f%10.3f%10.3f') doesn't give correct result but

pos= textscan(Line, '%f%f%s%f%f%f%f%f%f') does.

[sridhar]

changing 10.3%f to %f improved performance by 1.0 sec for each cycle, thats good.

the irregular text has no format, so cant use CommentStyle..

thanks!

Answer 2

[Fangjun Jiang]

Depending on your MATLAB version, you may try importdata(). In r2007b, it worked out well.

>> a=importdata('test.txt')
a = 
        data: [4x6 double]
    textdata: {4x3 cell}
>> a.data
ans =
   -3.4310    2.9600    2.0200    0.3250    0.2440    0.2300
   -3.4310    2.9600    2.0200    0.3250    0.2440    0.2300
   -3.4310    2.9600    2.0200    0.3250    0.2440    0.2300
   -3.4310    2.9600    2.0200    0.3250    0.2440    0.2300
>> a.textdata
ans = 
    '1'            '1'    'POSITION'
    '2'            '1'    'POSITION'
    [1x36 char]    '1'    'POSITION'
    '4'            '1'    'POSITION'
>> b=a.textdata
b = 
    '1'            '1'    'POSITION'
    '2'            '1'    'POSITION'
    [1x36 char]    '1'    'POSITION'
    '4'            '1'    'POSITION'
>> b{3,1}
ans =
asdasdsd

fasdasdasdasdasdsad

3