Thanks Jorge,
 
I am aware of the method you suggest, however, it's not quite what I was
asking for.
I was attempting to do this change on 56 dataframes, so I attempted to
do so with a list of all rather than each individually.
 
Thanks, DaveT.


________________________________

	From: Jorge Ivan Velez [mailto:jorgeivanvelez@gmail.com] 
	Sent: December 12, 2008 11:11 AM
	To: Thompson, David (MNR)
	Subject: Re: [R] assign()ing within apply
	
	

	Dear David, 

	Try this:

	ban.ovs.93[,'spp']<-tolower(ban.ovs.93[,'spp'])
	ban.ovs.93

	pem.ovs.94[,'spp']<-tolower(pem.ovs.94[,'spp'])
	pem.ovs.94


	HTH,
	
	Jorge
	
	
	
	On Fri, Dec 12, 2008 at 9:51 AM, Thompson, David (MNR)
<David.John.Thompson@ontario.ca> wrote:
	

		Any tips?
		
		DaveT.
		
		>-----Original Message-----
		>From: Thompson, David (MNR)
		>Sent: December 9, 2008 04:03 PM
		>To: 'r-help@r-project.org'
		>Subject: assign()ing within apply
		>
		>Hello,
		>
		>I'm trying to convert a character column in several
dataframes
		>to lower case.
		>
		>###
		>#
		># Sample data and 'spp' column summaries:
		># dput(ban.ovs.1993[sample(row.names(ban.ovs.1993),
20), 1:4])
		>ban.ovs.93 <- structure(list(oplt = c(43L, 43L, 38L,
26L, 35L,
		>8L, 39L, 1L,
		>34L, 50L, 10L, 29L, 31L, 24L, 18L, 12L, 27L, 49L, 28L,
51L),
		>    rplt = c(NA_integer_, NA_integer_, NA_integer_,
NA_integer_,
		>    NA_integer_, NA_integer_, NA_integer_, NA_integer_,
NA_integer_,
		>    NA_integer_, NA_integer_, NA_integer_, NA_integer_,
NA_integer_,
		>    NA_integer_, NA_integer_, NA_integer_, NA_integer_,
NA_integer_,
		>    NA_integer_), tree = c(427L, 410L, 639L, 494L,
649L, 166L,
		>    735L, 163L, 120L, 755L, 612L, 174L, 129L, 331L,
269L, 152L,
		>    552L, 227L, 243L, 96L), spp = c("MH", "MST", "MH",
"HE",
		>    "BE", "MH", "MH", "MH", "MH", "Or", "IW", "Or",
"MH", "MH",
		>    "BY", "MH", "MH", "BE", "MH", "MR")), .Names =
c("oplt",
		>"rplt", "tree", "spp"), row.names = c(4587L, 4570L,
3947L, 2761L,
		>3653L, 652L, 4136L, 64L, 3567L, 5318L, 838L, 3091L,
3366L, 2423L,
		>1775L, 1061L, 2893L, 5161L, 2967L, 5395L), class =
"data.frame")
		>
		># dput(pem.ovs.1994[sample(row.names(pem.ovs.1994),
20), 1:4])
		>pem.ovs.94 <- structure(list(oplt = c(8L, 17L, 36L, 9L,
31L,
		>11L, 35L, 51L,
		>51L, 49L, 40L, 1L, 9L, 17L, 4L, 42L, 6L, 3L, 39L, 25L),
tree = c(531L,
		>557L, 546L, 261L, 592L, 134L, 695L, 933L, 945L, 114L,
34L, 54L,
		>549L, 574L, 193L, 96L, 70L, 4L, 546L, 789L), spp =
c("MH", "MH",
		>"MH", "BF", "BF", "MH", "IW", "OR", "OR", "BF", "MH",
"IW", "OR",
		>"MH", "SM", "BE", "BE", "BE", "OR", "OR"), oaz = c(38L,
205L,
		>140L, 277L, 329L, 209L, 222L, 24L, 67L, 187L, 156L,
181L, 174L,
		>248L, 42L, 279L, 273L, 357L, 160L, 183L)), .Names =
c("oplt",
		>"tree", "spp", "oaz"), row.names = c(1204L, 2943L,
5790L, 1616L,
		>5063L, 2013L, 5691L, 8188L, 8200L, 7822L, 6302L, 54L,
1698L,
		>2960L, 421L, 6690L, 775L, 245L, 6205L, 4121L), class =
"data.frame")
		>
		># count per spp
		>invisible(lapply(ls(pat='ovs'), function(y) { cat(y,
"\n")  ;
		>print(summary.factor(get(y)[,'spp'])) ; cat("\n") } ) )
		>ban.ovs.93
		>BE  BY  HE  IW  MH  MR MST  Or
		> 2   1   1   1  11   1   1   2
		>
		>pem.ovs.94
		>BE BF IW MH OR SM
		> 3  3  2  6  5  1
		>#
		>###
		>
		>I have tried variants on the following and cannot
remember how
		>to have the result assign()ed back to the original
dataframes.
		>lapply(ls(pat='ovs'), function(y) { assign(paste(y,
		>"[,'spp']", sep=""), tolower(get(y)[,'spp'])) } )
		>
		>I *do* get the expected results:
		>[[1]]
		> [1] "mh"  "mst" "mh"  "he"  "be"  "mh"  "mh"  "mh"
"mh"
		>"or"  "iw"  "or"  "mh"  "mh"  "by"  "mh"  "mh"  "be"
"mh"  "mr"
		>
		>[[2]]
		> [1] "mh" "mh" "mh" "bf" "bf" "mh" "iw" "or" "or" "bf"
"mh"
		>"iw" "or" "mh" "sm" "be" "be" "be" "or" "or"
		>
		>, I just can't remember how to get them back into the
original
		>dataframe objects. Suggestions?
		>
		>Thanx, DaveT.
		>*************************************
		>Silviculture Data Analyst
		>Ontario Forest Research Institute
		>Ontario Ministry of Natural Resources
		>david.john.thompson@ontario.ca
		>http://ontario.ca/ofri
		>*************************************
		
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