import pandas as pd

df = pd.read_csv("DES5YR.FITRES.gz", comment="#", sep=r'\s+')

df = df.loc[df['HOST_DDLR'] >= 1]

df.to_csv("DES5YR_HIGH_DDLR.FITRES", sep=' ', index=False)

#
df = pd.read_csv("DES5YR.FITRES.gz", comment="#", sep=r'\s+')
df = df.loc[df['HOST_DDLR'] < 1]
df.to_csv("DES5YR_LOW_DDLR.FITRES", sep=' ', index=False)