Read a file into a list of vectors [closed]

Question

I have file structured as (Axis 1) (Axis 2) Data.
As an example:

1.2E-003 -0.500        0.0000000000000000     
1.2E-003 -0.493       1.53468784818295775E-004
1.2E-003 -0.487       5.89210645476378352E-004
1.2E-003 -0.481       1.23713800962565101E-003
1.2E-003 -0.475       1.99285240196946144E-003

2.8E-003 -0.500        0.0000000000000000     
2.8E-003 -0.493       1.65202052327590321E-004
2.8E-003 -0.487       6.34230407238311057E-004
2.8E-003 -0.481       1.33156043724947304E-003
2.8E-003 -0.475       2.14469618088317755E-003

In other words:

• Each line has 3 real values
• The data is divided in blocks separated by a blank line.
  • The size of each block is between 200 and 3000 (this size is unknown prior to reading the file, but I could write a shell script to extract and store this information somewhere if that makes things easier).
  • The first value is the same for the entire block.
• There are exactly 1000 blocks.

I would like Mathematica to open this file and store this information inside a variable. This variable would be a list of vectors.

In this list, each element (a vector) corresponds to 1 block, and this vector contains the data from the third column (all other data is discarded).

In this example, the variable should be a list of 2 vectors:

{{ 0.0000000000000000 , 1.53468784818295775E-004 , 5.89210645476378352E-004 , 1.23713800962565101E-003 , 1.99285240196946144E-003 },
 { 0.0000000000000000 , 1.65202052327590321E-004 , 6.34230407238311057E-004 , 1.33156043724947304E-003 , 2.14469618088317755E-003 }}

Is this easy to do?

Answer 1

Try:

ReadList["file.dat", {Number, Number, Number}] ~SplitBy~ First

Or:

SplitBy[Import["file.dat", "Table"], # === {} &] ~DeleteCases~ {{}}