[R] Why the result is coming as NULL?

[Julien Moeys]

Not sure, but maybe check the name of the column(s) you are retrieving

you may get a NULL value if the column name is misspelled

R example:
## --------------------------------------
df <- data.frame( 
    "Publication" = 1991:2000, 
    "Reference"   = LETTERS[1:10] )   

df[ 2, "References" ]
# NULL
## Notice the extra 's'
## --------------------------------------

If that does not fix your error, can you send us the output from

head(x)
# and
dput(head(x))

So we have an idea what your table looks like?

All the best

Julien

________________________________________
From: r-help-bounces at r-project.org [r-help-bounces at r-project.org] On Behalf Of Sri krishna Devarayalu Balanagu [balanagudevarayulu at gvkbio.com]
Sent: 01 August 2012 08:58
To: r-help at r-project.org
Subject: [R] Why the result is coming as NULL?

Why the result is coming as NULL. Can anyone help. I want to find the outliers for a reference


setwd("D:/AZ")

library("RODBC")
cdb_cnct <- odbcConnectExcel("Book1.xls")
cdb_frame <- sqlFetch(cdb_cnct, "Sheet1")
odbcClose(cdb_cnct)
rm(cdb_cnct)

x<- cdb_frame$Publication >=1990 & cdb_frame$Publication <=2012
invalid <- cdb_frame[!x, c("Reference")]
invalid

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