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Replace all values in an R data frame if they are greater than a certain value.
To replace all values in an R data frame if they are greater than a certain value, we can use apply function with ifelse function.
For Example, if we have a data frame called df and we want to replace all values in df with 5 if they are greater than 10 then we can use the command given below −
df[]<-apply(df,2,function(x) ifelse(x0,1,x))
Example 1
Following snippet creates a sample data frame −
x1<-rpois(20,1) x2<-rpois(20,1) x3<-rpois(20,1) df1<-data.frame(x1,x2,x3) df1
The following dataframe is created
x1 x2 x3 1 1 0 1 2 1 0 0 3 1 1 0 4 2 1 1 5 0 0 0 6 0 0 0 7 1 2 1 8 2 0 0 9 1 0 2 10 0 1 1 11 3 1 0 12 0 1 1 13 3 0 0 14 2 0 1 15 0 1 2 16 1 0 1 17 0 3 1 18 0 0 1 19 1 2 1 20 0 1 1
To replace all values in df1 with 1 if they are greater than 0 on the above created data frame, add the following code to the above snippet −
x1<-rpois(20,1) x2<-rpois(20,1) x3<-rpois(20,1) df1<-data.frame(x1,x2,x3) df1[]<-apply(df1,2,function(x) ifelse(x0,1,x)) df1
Output
If you execute all the above given snippets as a single program, it generates the following Output −
x1 x2 x3 [1,] 1 0 1 [2,] 1 0 0 [3,] 1 1 0 [4,] 1 1 1 [5,] 0 0 0 [6,] 0 0 0 [7,] 1 1 1 [8,] 1 0 0 [9,] 1 0 1 [10,] 0 1 1 [11,] 1 1 0 [12,] 0 1 1 [13,] 1 0 0 [14,] 1 0 1 [15,] 0 1 1 [16,] 1 0 1 [17,] 0 1 1 [18,] 0 0 1 [19,] 1 1 1 [20,] 0 1 1
Example 2
Following snippet creates a sample data frame −
y1<-round(rnorm(20),1) y2<-round(rnorm(20),1) y3<-round(rnorm(20),1) df2<-data.frame(y1,y2,y3) df2
The following dataframe is created
y1 y2 y3 1 -0.9 -0.2 -1.0 2 0.8 0.0 0.0 3 -0.2 0.6 -1.2 4 -0.5 0.5 1.2 5 1.1 1.2 1.2 6 0.2 -1.2 0.4 7 -2.2 -0.4 1.6 8 -0.7 0.0 -0.2 9 -0.4 1.1 -1.7 10 0.0 -1.0 0.6 11 0.1 -1.3 -0.1 12 0.7 0.0 -2.2 13 0.8 -0.1 0.5 14 -1.1 -0.3 -1.2 15 -0.4 1.3 -0.5 16 1.7 0.0 -0.3 17 -0.4 -2.4 -0.9 18 -0.5 2.1 0.6 19 0.2 1.1 -1.7 20 -0.3 0.1 -0.7
To replace all values in df2 with 0.5 if they are greater than 0.1 on the above created data frame, add the following code to the above snippet −
y1<-round(rnorm(20),1) y2<-round(rnorm(20),1) y3<-round(rnorm(20),1) df2<-data.frame(y1,y2,y3) df2[]<-apply(df2,2,function(x) ifelse(x0.1,0.5,x)) df2
Output
If you execute all the above given snippets as a single program, it generates the following Output −
y1 y2 y3 1 -0.9 -0.2 -1.0 2 0.5 0.0 0.0 3 -0.2 0.5 -1.2 4 -0.5 0.5 0.5 5 0.5 0.5 0.5 6 0.5 -1.2 0.5 7 -2.2 -0.4 0.5 8 -0.7 0.0 -0.2 9 -0.4 0.5 -1.7 10 0.0 -1.0 0.5 11 0.1 -1.3 -0.1 12 0.5 0.0 -2.2 13 0.5 -0.1 0.5 14 -1.1 -0.3 -1.2 15 -0.4 0.5 -0.5 16 0.5 0.0 -0.3 17 -0.4 -2.4 -0.9 18 -0.5 0.5 0.5 19 0.5 0.5 -1.7 20 -0.3 0.1 -0.7
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