Example 4

    from pyclimate.readdat import readdat
    from pyclimate.LanczosFilter import *
    
    a = readdat("data/filter.in.xy")
    
    npoints = 40
    file = open("data/filter.out.xy", "w")
    bp = LanczosFilter('bp', 0.025, 0.08, npoints)
    for i in range(len(a)):
      bfa = bp.getfiltered(a[i])
      if bfa:
        file.write("%d %f\n"%(i-npoints, bfa[1]))
    file.close()