Find data from txt file

Hi all,

I try to find a data from txt file. In a row (i don't known which row), there is an information like "Dt: 0.0001". I want to find this row and store 0.0001 as a variable. How can i do that?

Thanks for help

[Stephen23]

https://www.mathworks.com/help/matlab/ref/fileread.html

https://www.mathworks.com/help/matlab/ref/regexp.html

https://www.mathworks.com/help/matlab/ref/str2double.html

[Akira Agata]

How about using startsWith (to detect "DT:") + split (to split "DT" and data) + str2double (to covert to double)?

[KSSV]

Attach your text file.

[Cem Eren Aslan]

There are two types of txt file. I attach both of them below:

First txt type:

PEER STRONG MOTION DATABASE RECORD. PROCESSING BY PACIFIC ENGINEERING.

IMPERIAL VALLEY 5/19/40 0439, EL CENTRO ARRAY #9, 180 (USGS STATION 117)

ACCELERATION TIME HISTORY. FILTER POINTS: HP=0.2 Hz LP=15.0 Hz

NPTS= 4000, DT= .01000 SEC

Acceleration (m/sec2)

-0.06281522

-0.05914169

0.00520338

0.07596138

0.06759460

....

Second txt type:

Earthquake: Imperial Valley 10/15/79

Station: El Centro Array #11

Component: 230

Dt: 0.005 sec

# of Data: 7807

Source: PEER Strong Motion Database

Site Class: Z3

Acceleration (m/sec2)

0.0267573

0.0294902

0.011642

-0.0165857

-0.0165209

-0.0169276

.....

[Stephen23]

@Cem Eren Aslan: please upload a sample data file by clicking the paperclip button.

Answer 1

[Voss]

filename = 'file1.txt';
dt = str2double(regexpi(fileread(filename),'dt. (.*) sec','tokens','once'))

dt = 0.0100

filename = 'file2.txt';
dt = str2double(regexpi(fileread(filename),'dt. (.*) sec','tokens','once'))

dt = 0.0050

Answer 2

[Mathieu NOE]

Simply using the suggested methods , you can access your DT data this way

I simply created two data files from you post

I used lower to convert all characters to lower case which then ease the process

% first file 
out = fileread('data1.txt')

out = 
    'PEER STRONG MOTION DATABASE RECORD. PROCESSING BY PACIFIC ENGINEERING.
     IMPERIAL VALLEY 5/19/40 0439, EL CENTRO ARRAY #9, 180 (USGS STATION 117)
     ACCELERATION TIME HISTORY. FILTER POINTS: HP=0.2 Hz LP=15.0 Hz
     NPTS=  4000, DT= .01000 SEC
     Acceleration (m/sec2)
          -0.06281522
          -0.05914169
           0.00520338
           0.07596138
           0.06759460'

str = extractBetween(lower(out),'dt','sec');
A = regexp(str,'[-+]?([0-9]*[.])?[0-9]+([eE][-+]?\d+)?','match'); % extract numerical content of string
dt_value = str2double(A{1})

dt_value = 0.0100

% second file 
out = fileread('data2.txt')

out = 
    'Earthquake: Imperial Valley 10/15/79
     Station: El Centro Array #11
     Component: 230
     Dt: 0.005 sec
     # of Data: 7807
     Source: PEER Strong Motion Database
     Site Class: Z3
     Acceleration (m/sec2)
     0.0267573
     0.0294902
     0.011642
     -0.0165857
     -0.0165209'

str = extractBetween(lower(out),'dt','sec');
A = regexp(str,'[-+]?([0-9]*[.])?[0-9]+([eE][-+]?\d+)?','match'); % extract numerical content of string
dt_value = str2double(A{1})

dt_value = 0.0050

[Mathieu NOE]

hello again

problem solved ?

[Cem Eren Aslan]

Yes but not this way. I solved the problem by using AI. Thank you

[Voss]

@Cem Eren Aslan: What solution did AI give you?