convert data to binary in R using apply function

Question

I have a dataframe called reshapedwcw as follows. I want to use the apply function to convert the data to binary data where the value is present reshapewcw

    D009325 D009357 D009369 D009373 D009404 D009437 D009442 D009447  
r1    1       0       0       2       0       0       44      78        
r2    0       3       4       0       2       1       2       2 
r3    1       2       1       2       3       87      99      2

Desired Output

    D009325 D009357 D009369 D009373 D009404 D009437 D009442 D009447 
r1    1       0       0       1       0       0       1       1               
r2    0       1       1       0       1       1       1       1        
r3    1       1       1       1       1       1       1       1

In addition, kindly let me what is wrong with this approach and is there a better alternative

indices <- which(apply(reshapedwcw,2,function(x) x>1)) 
reshapedwcw[indices]<-1

Regarding why apply doesn't work, look at the indices it gives -- they are per-column, not positions in the full table. ycw's answer below shows the correct analog you can use. — Frank
– Frank, Commented Apr 11, 2017 at 16:21
@KHAN ifan I have updated my answer. My approach is not only valid for vector, but also valid for matrix and data frame. There is no need to use apply function. — www
– www, Commented Apr 12, 2017 at 10:04
@ycw what if I want to perform this operation from 3rd column to last column? can you write the syntax ? — KHAN irfan
– KHAN irfan, Commented Apr 12, 2017 at 10:14
@KHAN ifan temp_df <- reshapedwcw[, 3:8], temp_df[temp_df > 0] <- 1, reshapedwcw[, 3:8] <- temp_df — www
– www, Commented Apr 12, 2017 at 10:18

www · Accepted Answer · 2017-04-12 10:02:37Z

2

# Create the data frame
m <- matrix(c(1, 0, 0, 2, 0, 0, 44, 78,
              0, 3, 4, 0, 2, 1, 2, 2, 
              1, 2, 1, 2, 3, 87, 99, 2), 
              nrow = 3, byrow = TRUE)

reshapedwcw <- as.data.frame(m)
colnames(reshapedwcw) <- c("D009325", "D009357", "D009369", "D009373", 
                           "D009404", "D009437", "D009442", "D009447")
rownames(reshapedwcw) <- c("r1", "r2", "r3")

# Assign 1 to data larger than 0
reshapedwcw[reshapedwcw > 0] <- 1

edited Apr 12, 2017 at 10:02

answered Apr 11, 2017 at 16:19

www

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MrFlick · Accepted Answer · 2017-04-11 16:15:36Z

1

You can convert a binary value to 0/1 values by just adding 0. So you could just do

(reshapewcw>0)+0
#  009325 D009357 D009369 D009373 D009404 D009437 D009442 D009447 D009456 
#       1       0       0       1       0       0       1       1       0

answered Apr 11, 2017 at 16:15

MrFlick

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1 Comment

KHAN irfan Over a year ago

The reason I wanted to use the apply function is that I have other columns in the data frame that I do not want to disturb. Kindly observe the dataframe

PKumar · Accepted Answer · 2017-04-11 16:17:16Z

1

You can also do:

as.numeric(reshapewcw>0)

Thanks

answered Apr 11, 2017 at 16:17

PKumar

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