[R] problems with merge() - the output has many repeated lines

[Cecilia Carmo]

Hi everyone,

I have been merging many big dataframes (about 80000 rows 
each) and I never had this problem, but now it happened to 
me and I want to know if someone knows what could be 
happening.
The final dataframe has many rows, an impossible number! I 
have done edit(dataframe) and I saw that there are many 
repeated rows (all equal).

Thanks for any help,

Cecília Carmo
Universidade de Aveiro
Portugal