[R] replacing all NA's in a dataframe with zeros...

[Steven McKinney]

Since you can index a matrix or dataframe with
a matrix of logicals, you can use is.na()
to index all the NA locations and replace them
all with 0 in one command.

> mydata.df <- as.data.frame(matrix(sample(c(as.numeric(NA), 1), size = 30, replace = TRUE), nrow = 6))
> mydata.df
  V1 V2 V3 V4 V5
1  1 NA  1  1  1
2  1 NA NA NA  1
3 NA NA  1 NA NA
4 NA NA NA NA  1
5 NA  1 NA NA  1
6  1 NA NA  1  1
> is.na(mydata.df)
     V1    V2    V3    V4    V5
1 FALSE  TRUE FALSE FALSE FALSE
2 FALSE  TRUE  TRUE  TRUE FALSE
3  TRUE  TRUE FALSE  TRUE  TRUE
4  TRUE  TRUE  TRUE  TRUE FALSE
5  TRUE FALSE  TRUE  TRUE FALSE
6 FALSE  TRUE  TRUE FALSE FALSE
> mydata.df[is.na(mydata.df)] <- 0
> mydata.df
  V1 V2 V3 V4 V5
1  1  0  1  1  1
2  1  0  0  0  1
3  0  0  1  0  0
4  0  0  0  0  1
5  0  1  0  0  1
6  1  0  0  1  1
> 

Steven McKinney

Statistician
Molecular Oncology and Breast Cancer Program
British Columbia Cancer Research Centre

email: smckinney at bccrc.ca

tel: 604-675-8000 x7561

BCCRC
Molecular Oncology
675 West 10th Ave, Floor 4
Vancouver B.C. 
V5Z 1L3
Canada




-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch on behalf of David L. Van Brunt, Ph.D.
Sent: Wed 3/14/2007 5:22 PM
To: R-Help List
Subject: [R] replacing all NA's in a dataframe with zeros...
 
I've seen how to  replace the NA's in a single column with a data frame

*> mydata$ncigs[is.na(mydata$ncigs)]<-0

*But this is just one column... I have thousands of columns (!) that I need
to do this, and I can't figure out a way, outside of the dreaded loop, do
replace all NA's in an entire data frame (all vars) without naming each var
separately. Yikes.

I'm racking my brain on this, seems like I must be staring at the obvious,
but it eludes me. Searches have come up CLOSE, but not quite what I need..

Any pointers?

-- 
---------------------------------------
David L. Van Brunt, Ph.D.
mailto:dlvanbrunt at gmail.com

"If Tyranny and Oppression come to this land, it will be in the guise of
fighting a foreign enemy."
--James Madison

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