How to read a column named by some header in data file?

Dear All, I have 10 to 15 columns named with different headers in one data file (data.dat) (sample data file is attached below). The position of the column is not fixed and they can change after each run according to the inputs. Therefore, it is difficult to make a program with fixed column numbers. Is there any way to sort out the columns by their name and then proceed for other calculations? For example: Plot between Time and 2p2_3p1_4S___, multiplying any column by number (scalar), etc.

       Time      2p2_3p1_4S___   2p1_3p1_3D___   2p1_3d1_4F___   1s2_3p1_2P___
 1.0000000E-07   1.387545E-011   8.116580E-008   6.224102E-006   1.804010E-006
 2.0000000E-07   3.149958E-012   1.922005E-008   1.512518E-006   4.319076E-006
 3.0000000E-07   2.180968E-012   1.353958E-008   1.076323E-006   6.377379E-006
 4.0000000E-07   1.951598E-012   1.214133E-008   9.663528E-007   7.997309E-006
 5.0000000E-07   1.805993E-012   1.124047E-008   8.948846E-007   9.263814E-006
 6.0000000E-07   1.690790E-012   1.052642E-008   8.381780E-007   1.024948E-005
 7.0000000E-07   1.597212E-012   9.946256E-009   7.920958E-007   1.101235E-005
 8.0000000E-07   1.520693E-012   9.471772E-009   7.544044E-007   1.159861E-005
 9.0000000E-07   1.457775E-012   9.081556E-009   7.234037E-007   1.204494E-005
 1.0000000E-06   1.405719E-012   8.758646E-009   6.977473E-007   1.238051E-005
 1.1000000E-06   1.362348E-012   8.489555E-009   6.763642E-007   1.262849E-005
 1.2000000E-06   1.325931E-012   8.263553E-009   6.584026E-007   1.280729E-005
 1.3000000E-06   1.295089E-012   8.072101E-009   6.431845E-007   1.293155E-005
 1.4000000E-06   1.268726E-012   7.908405E-009   6.301705E-007   1.301287E-005
 1.5000000E-06   1.245968E-012   7.767055E-009   6.189311E-007   1.306048E-005
 1.6000000E-06   1.226121E-012   7.643745E-009   6.091243E-007   1.308170E-005
 1.7000000E-06   1.208630E-012   7.535042E-009   6.004778E-007   1.308236E-005
 1.8000000E-06   1.193055E-012   7.438214E-009   5.927743E-007   1.306706E-005
 1.9000000E-06   1.179043E-012   7.351078E-009   5.858408E-007   1.303945E-005
 2.0000000E-06   1.166313E-012   7.271897E-009   5.795392E-007   1.300244E-005

Your kind help will be highly appreciated. Thanks

[Stephen23]

@prashant sharma: what MATLAB version are you using?

[prashant sharma]

Hi Stephen, I am using Matlab 8.3 (R2014a). Thanks

[Stephen23]

Then readtable is your best option, and you can access the variables of the table using the header names.

Answer 1

[madhan ravi]

Use

T=readtable('data.txt');

T.Time %finds column header with Time 
  ^^^^|______________________________________%denotes column header

T.x2p1_3d1_4F___ = T.x2p1_3d1_4F___ * 2;

why x in front of 2 see comment

Then how will I write a program which read the data file and then searches the header for 2p1_3d1_4F___

You don't have to , if you specify the header name it will do the work for you

[prashant sharma]

Hi,

For example, I want to multiply 2p1_3d1_4F___ column with 2 (scalar). Then how will I write a program which read the data file and then searches the header for 2p1_3d1_4F___ and after finding the column, it will multiply the data values by 2.

[madhan ravi]

see edited answer

[Guillaume]

Yes, as Stephen and Madhan have said, use readtable. In most cases, and certainly with your example file, a plain readtable is all that is needed to read the file correctly, with headers.

However note that table variables (headers) need to be valid variable names, and thus cannot start with a number. As a result, you may see a warning and matlab will change the 2p1_3d1_4F___ into something valid, most likely, x2p1_3d1_4F___.

T = readtable('data.txt');
T.x2p1_3d1_4F___ = T.x2p1_3d1_4F___ * 2;

[madhan ravi]

Thank you @Guillaume for the perfect explanation

[prashant sharma]

Thank you very much for the help... @madhan @Guillaume

[madhan ravi]

Anytime :)