deleting rows of a data frame with specific condition

I've seen similar questions here, but I couldn't find any help.

I have a df like this:

df <- data.frame(CSF1=c(-9,-9,-9,-9), CSF2=c(-9,-1,-9,-9), 
               D13S1=c(-9,-9,11,11), D13S2=c(-9,-9,11,12))

         CSF1 CSF2 D13S1 D13S2 
10398     -9   -9   -9    -9                   
10398     -9   -1   -9    -9                             
20177     -9   -9   11    11                  
20361     -9   -9   11    12           

I want to delete all the rows with values -9 or -1 for all columns, like the first 2 rows.

Thanks!

Answers


Try this (edited by Arun to account for Dov's post):

df[rowSums(df == -1 | df == -9, na.rm = TRUE) != ncol(df), ]
##   CSF1 CSF2 D13S1 D13S2
## 3   -9   -9    11    11
## 4   -9   -9    11    12

(df == -1 | df == -9) will give you logical matrix. rowSums will give you count of TRUE in each row since TRUE is evaluated as 1. The na.rm=TRUE is to ensure that rows with NA are not omitted (see Dov's post). Use resultant row numbers to subset df.


All I will add is that the which function doesn't appear to be necessary. Removing it yields the same result.

There is a secondary problem that you would have in situations with missing data. If, you add an NA to the 3rd row (try it with df[3,4] <- NA), then the output of the above solution will omit the 3rd row as well regardless of the other entries' values. I won't suggest alternatives as this may not be a problem for your data set.


Need Your Help

Latex listings-package format option for uppercase keywords

latex listings uppercase

I use the listings package to insert source code. I would like to print all keywords uppercase in the output, regardless of the case in the input.

About UNIX Resources Network

Original, collect and organize Developers related documents, information and materials, contains jQuery, Html, CSS, MySQL, .NET, ASP.NET, SQL, objective-c, iPhone, Ruby on Rails, C, SQL Server, Ruby, Arrays, Regex, ASP.NET MVC, WPF, XML, Ajax, DataBase, and so on.