R help - Mar 2011 - How to substract a valur from dataframe with condition

Hello All,

I need help with my dataframe, it is big but here I am using a small table
as an example.

My dataframe df looks like:
        X1      X2    X3
1   2011-02  0.00 96.00
2   2011-02  0.00  2.11
3   2011-02  2.00  3.08
4   2011-02  0.06  2.79
5   2011-02  0.00 96.00
6   2011-02  0.00 97.00
7   2011-02  0.08  2.23

I want values in columns X2 and X3 to be checked if they are greater than
50, if yes, then subtract from '100'

df should look like:

       X1      X2    X3
1   2011-02  0.00 4.00
2   2011-02  0.00  2.11
3   2011-02  2.00  3.08
4   2011-02  0.06  2.79
5   2011-02  0.00 4.00
6   2011-02  0.00 3.00
7   2011-02  0.08  2.23


Please help, I will really appreciate that.

Thanks,

Joe




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On Mar 21, 2011, at 5:39 PM, joe82 wrote:
> Hello All,
>
> I need help with my dataframe, it is big but here I am using a small  
> table
> as an example.
>
> My dataframe df looks like:
>        X1      X2    X3
> 1   2011-02  0.00 96.00
> 2   2011-02  0.00  2.11
> 3   2011-02  2.00  3.08
> 4   2011-02  0.06  2.79
> 5   2011-02  0.00 96.00
> 6   2011-02  0.00 97.00
> 7   2011-02  0.08  2.23
>
> I want values in columns X2 and X3 to be checked if they are greater  
> than
> 50, if yes, then subtract from '100'
>
> df should look like:
>
>       X1      X2    X3
> 1   2011-02  0.00 4.00
> 2   2011-02  0.00  2.11
> 3   2011-02  2.00  3.08
> 4   2011-02  0.06  2.79
> 5   2011-02  0.00 4.00
> 6   2011-02  0.00 3.00
> 7   2011-02  0.08  2.23

df[ , 2:3] <- apply(df[ , 2:3], 2,
                  function(x) ifelse(x >50, 100-x, x) )

OR:

df[ , 2:3] <- sapply(df[ , 2:3],
                  function(x) ifelse(x >50, 100-x, x) )

(or lapply would work as well)

OR;

df$X2[df$X2 >50] <- 100 - df$X2[df$X2 >50]
df$X1[df$X1 >50] <- 100 - df$X1[df$X1 >50]

-- 
David Winsemius, MD
Heritage Laboratories
West Hartford, CT

dat <- within(dat, {
	X2 <- ifelse(X2 > 50, 100-X2, X2)
	X3 <- ifelse(X3 > 50, 100-X3, X3)
})
 

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of joe82
Sent: Tuesday, 22 March 2011 7:40 AM
To: r-help at r-project.org
Subject: [R] How to substract a valur from dataframe with condition

Hello All,

I need help with my dataframe, it is big but here I am using a small table
as an example.

My dataframe df looks like:
        X1      X2    X3
1   2011-02  0.00 96.00
2   2011-02  0.00  2.11
3   2011-02  2.00  3.08
4   2011-02  0.06  2.79
5   2011-02  0.00 96.00
6   2011-02  0.00 97.00
7   2011-02  0.08  2.23

I want values in columns X2 and X3 to be checked if they are greater than
50, if yes, then subtract from '100'

df should look like:

       X1      X2    X3
1   2011-02  0.00 4.00
2   2011-02  0.00  2.11
3   2011-02  2.00  3.08
4   2011-02  0.06  2.79
5   2011-02  0.00 4.00
6   2011-02  0.00 3.00
7   2011-02  0.08  2.23


Please help, I will really appreciate that.

Thanks,

Joe




--
View this message in context:
http://r.789695.n4.nabble.com/How-to-substract-a-valur-from-dataframe-with-condition-tp3394907p3394907.html
Sent from the R help mailing list archive at Nabble.com.

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On 2011-03-21 14:39, joe82 wrote:
> Hello All,
>
> I need help with my dataframe, it is big but here I am using a small table
> as an example.
>
> My dataframe df looks like:
>          X1      X2    X3
> 1   2011-02  0.00 96.00
> 2   2011-02  0.00  2.11
> 3   2011-02  2.00  3.08
> 4   2011-02  0.06  2.79
> 5   2011-02  0.00 96.00
> 6   2011-02  0.00 97.00
> 7   2011-02  0.08  2.23
>
> I want values in columns X2 and X3 to be checked if they are greater than
> 50, if yes, then subtract from '100'
>
> df should look like:
>
>         X1      X2    X3
> 1   2011-02  0.00 4.00
> 2   2011-02  0.00  2.11
> 3   2011-02  2.00  3.08
> 4   2011-02  0.06  2.79
> 5   2011-02  0.00 4.00
> 6   2011-02  0.00 3.00
> 7   2011-02  0.08  2.23
>
One more way:

  d <- transform(d,
                   X1 = pmin(X1, 100 - X1),
                   X2 = pmin(X2, 100 - X2))

[or use within() in place of transform()].

Peter Ehlers