Find data from txt file

Question

Cem Eren Aslan 2024-4-29

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2113051-find-data-from-txt-file

评论： Voss 2024-5-29

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

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Cem Eren Aslan 2024-4-30

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 2024-4-30

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

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Answer 1

Voss 2024-4-30

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2113051-find-data-from-txt-file#answer_1450366

编辑：Voss 2024-4-30

在 MATLAB Online 中打开

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

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Answer 2

Mathieu NOE 2024-4-30

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2113051-find-data-from-txt-file#answer_1450356

在 MATLAB Online 中打开

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