how to process multiple data files using R loop

 for(i in ls(pattern="P_")){ head(get(i), 2)}  # Should work.

On Aug 8, 2014, at 11:25 AM, Fix Ace wrote:

I have 16 files and would like to check the information of their first two lines, what I did:

ls(pattern="P_")

 [1] "P_3_utr_source_data"               "P_5_utr_source_data"
 [3] "P_exon_per_gene_cds_source_data"   "P_exon_per_gene_source_data"
 [5] "P_exon_source_data"                "P_first_exon_oncds_source_data"
 [7] "P_first_intron_oncds_source_data"  "P_first_intron_ongene_source_data"
 [9] "P_firt_exon_ongene_source_data"    "P_gene_cds_source_data"
[11] "P_gene_source_data"                "P_intron_source_data"
[13] "P_last_exon_oncds_source_data"     "P_last_exon_ongene_source_data"
[15] "P_last_intron_oncds_source_data"   "P_last_intron_ongene_source_data"

The results from `ls()` are not actual R names but rather are character vectors. To "promote" a character value to an R language-name you need the `get` function:

for(i in ls(pattern="P_")){head(i, 2)}

 for(i in ls(pattern="P_")){ head(get(i), 2)}  # Should work.

David.

It obviously does not work since nothing came out

What I would like to see for the output is :

head(P_3_utr_source_data,2)

  V1
1  1
2  1

head(P_5_utr_source_data,2)

  V1
1  1
2  1

.

.
.



Could anybody help me with this?

Thank you very much for your time:)
      [[alternative HTML version deleted]]

David Winsemius
Alameda, CA, USA