Best way to read/analysis reoccurring data in a file

Question

I want to know what is the best/easiest way to read and analysis reoccurring data from a file with python. E.g. file:

some text
some more text
x y z
23 23 45
45 67 89
23 64 67
some text
some more text
x y z
23 23 45
45 67 89
23 64 67
.
.
.
.

I want to read the xyz data and determine the change over the occurrences. I'm wondering if there is a better way then reading line by line and using an if statement to find and separate the numerical data. If the data was in different files I would loop over the file names and use np.loadtxt. For some reason I find it harder to deal with reoccurring data in a file then multiple files. Thanks for any help.