a = [['P101','John','Jones','100'], ['P102','Steve','Woodhouse','500'], ['P103','Ben','Jacobs','60']]
b = [['P101','John','Jones','250'], ['P102','Steve','Woodhouse','500']]
ad = { p[0]: "{} {}".format(p[1],p[2]) for p in a}
bd = { p[0]: "{} {}".format(p[1],p[2]) for p in b}
common_id = ad.viewkeys() & bd.viewkeys()
for id in common_id:
print ad[id]
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