Using string compare on imported data

I am very new to Matlab and have only ever used maple. I am trying to use string compare on huge imported data (26,000 rows) to a specific word to find the row that contains it.

I understand the basics of strcmp and can use it within matlab, but cannot figure out how to use it for a data set. So for example, I am currently working with the code:

s1 = 'RT'; s2 = {ImpD(:,4)}; TF = strcmp(s1, s2); find(TF);

ImpD(:,4) since I am looking for the specific text in the 4th column. I just don't think Matlab is realizing I am referencing the imported data. How can i fix this?

[Guillaume]

what is

class(ImpD)

and if it cell, what is

class(ImpD{1, 4})

[Jacob Barrett-Newton]

Its returning it as a table. So that class(ImpD{1,4}) is a string

[Jacob Barrett-Newton]

Ah, I think your comment has just helped me to fix things. I had it imported as a table, i imported it as a string array and it seems to have returned what i want. Like i said I am very new to this. Thanks for helping me to realise

[Jacob Barrett-Newton]

Is there a way to make this into a loop? As I have about 20 words i need to find in this massive data set, which i could do individually but it would be nice to be able to write a loop that will do it all at once

[Guillaume]

Is it string or char array? People use the two interchangeably but they are actually two very different types. comparisons are easier with strings.

Since ImpD is a table, what is the name of the fourth column?

[Jacob Barrett-Newton]

Well now that i have imported it as a string array, class(ImpD) returns string and class(ImpD{1, 4}) returns char

Answer 1

[Guillaume]

If ImpD is a string array with a least four columns:

ismatch = ImpD(:, 4) == "RT"

to find "RT" in the fourth column.

If it were a table as you had initially:

ismatch = ImpD{:, 4} == "RT"
%or
ismatch = ImpD.column4name == "RT"  %replace column4name by actual name

If you're going to wrap the above in a loop to find different strings and do something then it is very likely that there is a much better way. A better explanation of what you want to achieve and of the starting point would be required.

[Jacob Barrett-Newton]

well after I identify which rows contain which bit of text, I can then extract the values from the corresponding columns and plot it. The required text is also imported. Its a table with the text i need in the second column. At the moment now that I can find the row I can just one by one search for it, but like I said being able to loop it would make it a lot cleaner and easier.