[R] Removing rows if certain elements are found in character string

[MacQueen, Don]

Perhaps I've missed something, but if it's really true that the goal is to
remove rows if the first non-zero element is "D" or "d", then how about
this:

tmp <- gsub('0','',df$ch)
first <- substr(tmp,1,1)
subset(df, tolower(first) != 'd')

and of course it could be rolled up into a single expression, but I wrote
it in several steps to make it easy to follow. No need to wrap one's brain
around regular expressions (which is hard for me!)

-Don

-- 
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 7/2/12 3:48 PM, "Claudia Penaloza" <claudiapenaloza at gmail.com> wrote:

>I would like to remove rows from the following data frame (df) if there
>are
>only two specific elements found in the df$ch character string (I want to
>remove rows with only "0" & "D" or "0" & "d"). Alternatively, I would like
>to remove rows if the first non-zero element is "D" or "d".
>
>
>                                                 ch     count
>1  0000000000D0000000000000000000000000000000000000 0.007368;
>2  0000000000d0000000000000000000000000000000000000 0.002456;
>3  000000000T00000000000000000000000000000000000000 0.007368;
>4  000000000TD0000000000000000000000000000000000000 0.007368;
>5  000000000T00000000000000000000000000000000000000 0.002456;
>6  000000000Td0000000000000000000000000000000000000 0.002456;
>7  00000000T000000000000000000000000000000000000000 0.007368;
>8  00000000T0D0000000000000000000000000000000000000 0.007368;
>9  00000000T000000000000000000000000000000000000000 0.002456;
>10 00000000T0d0000000000000000000000000000000000000 0.002456;
>
>
>I tried the following but it doesn't work if there is more than one
>character per string:
>
>>df <- df[!df$ch %in% c("0","D"),]
>>df <- df[!df$ch %in% c("0","d"),]
>
>Any help greatly appreciated,
>Claudia
>
>	[[alternative HTML version deleted]]
>
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