[R] using if then statements in a dataframe

[Weidong Gu]

Mike,

One thing I noticed that '&&' should be replaced by '&'. The former is
applied to the first element of the vector while the latter applicable
to the whole vector.


HTH

Weidong Gu

On Wed, Aug 10, 2011 at 7:34 PM, Ward, Michael Patrick
<mpward at illinois.edu> wrote:
>
> I used this service several months ago and was very pleased with the response.
>
> I have a dataframe with several thousand lines and to each line I need to apply a series of "if else" statements. For each row I need either a value or a blank/NA. Below is the series of if else statements I have been trying without success to integrate into a function such as "apply".
>
> if (t1.secondstrongest<-13000) {NA} else
> if (noise>-13000) {NA} else
> if ((abs(value.str1-value.str2))==120) {NA} else
> if ((abs(value.str1-value.str2))==180) {NA} else
> if ((abs(value.str1-value.str2))==240) {NA} else
> if (value.str1 ==300&&value.str2 ==0) {value.str1_adj+ bearingdiff} else
> if (value.str1 ==0&&value.str2 ==360) {value.str1_adj+360 - bearingdiff} else
> if (value.str2<value.str1) {value.str1_adj-bearingdiff} else
> if (value.str2>value.str1) {value.str1_adj+bearingdiff}
>
>
> Below is an example of the dataframe
>
> t1.secondstrongest         Ant_test              value.str1            value.str1_adj                   value.str2            value.str2_adj                   Noise                    bearingdiff
> 1              -10682                                  60                           240                         242                                         180                                         182                         -12344                   11.23
> 2              -11154                                  240                         0                              2                                              240                                         242                         -13444                   27.23
> 3              -10930                                   300                        0                              2                                              300                                         302                         -14022                   27.55
> 4              -10997                                   240                         300                        302                                         60                                           62                           -13456                   14.23
> 5              -11244                                  180                          180                        182                                         0                                              2                              -14209                   25.22
> 6              -12744                                    60                          180                        182                                         240                                         242                         -14134                   8.13
>
> The answer to the examples should be...
>
> 1                     NA
>
> 2                     NA
>
> 3                     334.45
>
> 4                     NA
>
> 5                     NA
>
> 6                     190.13
>
>
> THANKS!
> Mike
> Department of Natural Resources and Environmental Sciences
> University of Illinois
>
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>
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