[R] Finding Source of Error Message of 'Non-Unique Index Entries'

[Rich Shepard]

   I have a situation that I cannot resolve by myself. When I try to create a
zoo object (with read.zoo() ) I get this error:

Error in merge.zoo(`BC-0.5 = c("   0.000", "   0.010", "   0.010", "
0.060",  :
   series cannot be merged with non-unique index entries in a series

   This suggests that there is a duplicate entry for the factor BC-0.5 on a
given date. Because the data originate in a relational database table with
a multi-column primary key there are no duplicate rows in the table, or the
text file copied from that table. I need to find the source of this error.

   How can I identify the non-unique index entries within R?

Rich