[zephyrus17]

I have a set of data generated from a Fortran run that simulates fuel spray into a cylinder. The cylinder is represented by a 1deg slice. The data set has X, Y, Z coordinates, and various variables like temperature, mixture fraction, O2 mass fraction, etc, all in one row.

I would like to plot mixture fraction with respect to cylinder radius, but only at a certain axial distance (20 mm). However, the data is generated by first keeping Y and Z constant (radius and angle), and increasing X (axial distance). After X has cycled to the maximum, Y is increased one step and then X is increased again.

The way the data is set makes it quite hard to get data only at X=20mm, because the corresponding Y value only occurs every 158 lines. Is there a way to extract data every 158 lines so I make the plot I need? Thank you so much!