Removing specific lines from a .txt file.

I have a .txt file that I have imported into MATLAB and I need to remove some specific lines. Currently, I have simplified it to what I have shown below:

Trace = 'D:\trace.txt';

%Simplify trace file into time and status matrix
str = fileread(Trace);
trace = regexp(str, '^(\d+\.?\d*):[^:]+:\s+([^\n\r,]+)','tokens','lineanchors');
trace = vertcat(trace{:});

%Simplify trace file to display only desired keywords
trace(strcmp(trace(:,2), 'init-hold'),:) = [];
trace(strcmp(trace(:,2), 'start'),:) = [];
trace(strcmp(trace(:,2), 'vent-check'),:) = [];
trace(strcmp(trace(:,2), 'flush'),:) = [];
trace(strcmp(trace(:,2), 'flush-evac'),:) = [];
trace(strcmp(trace(:,2), 'flush-vent'),:) = [];
trace(strcmp(trace(:,2), 'init-evac'),:) = [];
trace(strcmp(trace(:,2), 'leak-test-end'),:) = [];
trace(strcmp(trace(:,2), 'pre-leak-test'),:) = [];
trace(strcmp(trace(:,2), 'leak-test'),:) = [];
trace(strcmp(trace(:,2), 'pre-ramp'),:) = [];
trace(strcmp(trace(:,2), 'ramp'),:) = [];
trace(strcmp(trace(:,2), 'evac'),:) = [];
trace(strcmp(trace(:,2), 'vent'),:) = [];
trace(strcmp(trace(:,2), 'done'),:) = [];
trace(strcmp(trace(:,2), 'end-vent'),:) = []

Where I end up with the following result:

{'14667.4'      }    {'hold'                  }
{'18267.4'      }    {'hold-end'              }
{'18456.4'      }    {'hold'                  }
{'22056.4'      }    {'hold-end'              }
{'22245.6'      }    {'hold'                  }
{'25845.6000001'}    {'max-pressure-evac 60.0'}
{'26034.6000001'}    {'max-pressure-evac 60.0'}
{'29634.6000001'}    {'hold-end'              }
{'29823.6000001'}    {'hold'                  }
{'31332.4000001'}    {'hold-end'              }
{'32785.4000001'}    {'hold'                  }
{'33423.6000001'}    {'hold-end'              }

I want my code to be able to recognize when a 'max-pressure-evac 60.0' follows a 'hold' and then to remove only the lines between that initial 'hold' and the next 'hold-end'. For the above example I would want the following output:

{'14667.4'      }    {'hold'                  }
{'18267.4'      }    {'hold-end'              }
{'18456.4'      }    {'hold'                  }
{'22056.4'      }    {'hold-end'              }
{'29823.6000001'}    {'hold'                  }
{'31332.4000001'}    {'hold-end'              }
{'32785.4000001'}    {'hold'                  }
{'33423.6000001'}    {'hold-end'              }

Where the four lines corresponding to the 22245.6-29634.6000001 timestamps have been removed but everything else was kept. Any help would be greatly appreciated! I have attached an example .txt file for reference.

Answer 1

[Mitch Lautigar]

As you read this in, you really just need to add in a conditional flag. Specifically, if a "hold" is seen, set a hold_flag to be true (you can use setappdata/getappdata to move flags around like a global variable without it actually being a global value) you do not record any lines into your new array. If the hold_flag is false, then you record normally.