This is my code, trying to convert the second field of the line from exponential into float.
outputrrd = processrrd.communicate() (output, error) = outputrrd
The reason is the use of comma in 6,0865000000e-01. This won't work because float() is not locale-aware. See PEP 331 for details.
6,0865000000e-01
float()
Try locale.atof(), or replace the comma with a dot.