Find a substring in table

Hi,

I'm struggling with finding the rows of columns that contains a certain substring (e.g. '.jpg') in a table column?

Any suggestions?

Kati

Answer 1

[Lei Hou]

Hi Katharina,

You can make use of table indexing to get that data you want. I’ll use a simple example below to illustrate the output.

Suppose the table is like the following:

Var1 Var2 Var3

___________ ____ ____________

"file1.png" 1 "Image1.jpg"

"file2.jpg" 2 "Image2.jpg"

"file3.gif" 3 "Image3.gif"

"file4.jpg" 4 "Image4.png"

If you want to check which rows of column ‘Var1’ end with ‘.jpg’ and return those rows with all columns, here is the solution.

>> t1 = t(endsWith(t.Var1,'.jpg'),:);

The output 't1' is like the following

Var1 Var2 Var3

___________ ____ ____________

"file2.jpg" 2 "Image2.jpg"

"file4.jpg" 4 "Image4.png"

I’m not sure whether I understand your question correctly. If not, please provide more information about your use case or illustrate your expected output with my simple example.

Answer 2

[katharina voigt]

Thanks Lei for your response.

My question has changed a bit, but in essence it is the same.

I would like to have the row number, when t.Code == 'Response:' (the digits behind response can change and that is why i would like to have it more flexible.

So at the moment I tried this

startsWith(t.Code,'Response')

However, I get the following error:

Error using contains
Search term must be a string array, character vector, or cell array of character vectors.

Following this i tried

startsWith(cell(t.Code),'Response')

But it said that the conersion to cell from categorical is not possible.

Please find table (t) attached.

Thank you very much in advance.

Answer 3

[Lei Hou]

Hi Katharina,

You should cellstr to convert the categorical data to a cell array of character vectors as:

startsWith(cellstr(t.Code),'Response')

You can also call string to convert the categorical data to a string array as:

startsWith(string(t.Code),'Response')

Since R2018b, it is highly recommended to use string instead of cellstr when you work with text because string is more efficient.