Ifelse with NA values in columns - r

I am trying to apply an ifelse statement on columns that have NA and would like the else condition to be given when NA is present. Instead, I just get NA. My actual case uses multiple columns making it difficult for me to find a solution (e.g., I can't convert NA's to 0 because there are some cases that are missing across all columns).
Data:
df <- data.frame(a=c(NA, 1:3, NA) , b=c(NA,4:6,NA), c=c(5,10,15,20,25))
a b c
1 NA NA 5
2 1 4 10
3 2 5 15
4 3 6 20
5 NA NA 25
Attempt:
df2 <- df %>% mutate(check=ifelse((a<=2&b>4)|c==25,1,0))
Result:
a b c check
1 NA NA 5 NA
2 1 4 10 0
3 2 5 15 1
4 3 6 20 0
5 NA NA 25 1
Desired output:
a b c check
1 NA NA 5 **0**
2 1 4 10 0
3 2 5 15 1
4 3 6 20 0
5 NA NA 25 1

You can deal with the na's in a separate line:
df2 <- df %>%
#mutate_at(vars("a", "b", "c"), ~if_else(is.na(.x), 0.0, as.double(.x))) %>% # double?
mutate_at(vars("a", "b", "c"), ~if_else(is.na(.x), 0L, as.integer(.x))) %>% # or integer
mutate(check=ifelse((a<=2&b>4)|c==25,1,0))

Let's combine previous comment into the script:
library(dplyr)
df <- data.frame(a=c(NA, 1:3, NA) , b=c(NA,4:6,NA), c=c(5,10,15,20,25))
df2 <- df %>% mutate(check=ifelse((a<=2&b>4)|c==25,1,0))
# if dataset 2 contains NA, transform into 0
df2$check[is.na(df2$check)] <- 0

My answer is not exactly what you want, but if you want to replace NA values, you can try this one
df[is.na(df)] <- 0
Output
a b c
1 0 0 5
2 1 4 10
3 2 5 15
4 3 6 20
5 0 0 25

Related

Conditionally replace NAs in Certain Columns Based on Row Values

For a dataframe like I have below, I am trying to selectively replace the NAs in columns a, b, and c with a 0 using R, but only when there is at least one missing value in those columns for that row.
For example, I would want to replace the NAs in rows 1,2, and 5, but leave row 4 alone, and not replace the NA in column d
sample data
df <- data.frame(a = c(1,NA,2,NA,3,4),
b = c(NA,5,6,NA,7,8),
c = c(9,NA,10,NA,NA,11),
d = c("Alpha","Beta","Charlie","Delta",NA,"Foxtrot"))
> df
a b c d
1 1 NA 9 Alpha
2 NA 5 NA Beta
3 2 6 10 Charlie
4 NA NA NA Delta
5 3 7 NA <NA>
6 4 8 11 Foxtrot
Desired outcome
> df_naReplaced
a b c d
1 1 0 9 Alpha
2 0 5 0 Beta
3 2 6 10 Charlie
4 NA NA NA Delta
5 3 7 0 <NA>
6 4 8 11 Foxtrot
The solutions that I have found so far only work on conditions by column, but not by row, or would require actively removing those columns from their context (in this example separating it from d).
I have tried using ifelse and an if statement like below but was unable to get it to work as selectively as I would like, as it replaces all NA in that column.
if(df %>% select(a:c) %>% any(!is.na(.))){
df<- df %>% replace_na(list(a= 0,
b= 0,
c= 0)
)
}
Thank you for whatever help you are able to offer!
Here's an R base solution
> df[,-4][(is.na(df[, -4]) & rowSums(is.na(df[, -4])) < 3)] <- 0
> df
a b c d
1 1 0 9 Alpha
2 0 5 0 Beta
3 2 6 10 Charlie
4 NA NA NA Delta
5 3 7 0 <NA>
6 4 8 11 Foxtrot

Custom data frame in R

I have a below data frame
df <- data.frame(a = c(1,3,4,5,8,9), b = c("","",0,0,"",""))
df$b <- as.numeric(df$b)
df
a b
1 1 NA
2 3 NA
3 4 0
4 5 0
5 8 NA
6 9 NA
Is there a way to populate the data frame that is capturing the value in column a only at a specific point
Example : Expected output (a cell before 0 and after 0 in column b should be filled by the value in column a.
df1
a b
1 1 NA
2 3 3
3 4 0
4 5 0
5 8 8
6 9 NA
I think the following solution will help you:
library(dplyr)
df %>%
mutate(b = ifelse(is.na(b) & lead(b) == 0 | is.na(b) & lag(b) == 0, a, b))
a b
1 1 NA
2 3 3
3 4 0
4 5 0
5 8 8
6 9 NA

R: creating multiple new variables based on conditions of selection of other variables with similar names

I have a data frame where each condition (in the example: hope, dream, joy) has 5 variables (in the example, coded with suffixes x, y, z, a, b - the are the same for each condition).
df <- data.frame(matrix(1:16,5,16))
names(df) <- c('ID','hopex','hopey','hopez','hopea','hopeb','dreamx','dreamy','dreamz','dreama','dreamb','joyx','joyy','joyz','joya','joyb')
df[1,2:6] <- NA
df[3:5,c(7,10,14)] <- NA
This is how the data looks like:
ID hopex hopey hopez hopea hopeb dreamx dreamy dreamz dreama dreamb joyx joyy joyz joya joyb
1 1 NA NA NA NA NA 15 4 9 14 3 8 13 2 7 12
2 2 7 12 1 6 11 16 5 10 15 4 9 14 3 8 13
3 3 8 13 2 7 12 NA 6 11 NA 5 10 15 NA 9 14
4 4 9 14 3 8 13 NA 7 12 NA 6 11 16 NA 10 15
5 5 10 15 4 9 14 NA 8 13 NA 7 12 1 NA 11 16
I want to create a new variable for each condition (hope, dream, joy) that codes whether all of the variables x...b for that condition are NA (0 if all are NA, 1 if any is non-NA). And I want the new variables to be stored in the data frame. Thus, the output should be this:
ID hopex hopey hopez hopea hopeb dreamx dreamy dreamz dreama dreamb joyx joyy joyz joya joyb hope joy dream
1 1 NA NA NA NA NA 15 4 9 14 3 8 13 2 7 12 0 1 1
2 2 7 12 1 6 11 16 5 10 15 4 9 14 3 8 13 1 1 1
3 3 8 13 2 7 12 NA 6 11 NA 5 10 15 NA 9 14 1 1 1
4 4 9 14 3 8 13 NA 7 12 NA 6 11 16 NA 10 15 1 1 1
5 5 10 15 4 9 14 NA 8 13 NA 7 12 1 NA 11 16 1 1 1
The code below does it, but I'm looking for a more elegant solution (e.g., for a case where I have even more conditions). I've tried with various combinations of all(), select(), mutate(), but while they all seem useful, I cannot figure out how to combine them to get what I want. I'm stuck and would be interested in learning to code more efficiently. Thanks in advance!
df$hope <- 0
df[is.na(df$hopex) == FALSE | is.na(df$hopey) == FALSE | is.na(df$hopez) == FALSE | is.na(df$hopea) == FALSE | is.na(df$hopeb) == FALSE, "hope"] <- 1
df$dream <- 0
df[is.na(df$dreamx) == FALSE | is.na(df$dreamy) == FALSE | is.na(df$dreamz) == FALSE | is.na(df$dreama) == FALSE | is.na(df$dreamb) == FALSE, "dream"] <- 1
df$joy<- 0
df[is.na(df$joyx) == FALSE | is.na(df$joyy) == FALSE | is.na(df$joyz) == FALSE | is.na(df$joya) == FALSE | is.na(df$joyb) == FALSE, "joy"] <- 1
Here is an option with tidyverse
library(dplyr)
library(purrr)
library(magrittr)
df %>%
mutate(hope = select(., starts_with('hope')) %>%
is.na %>%
`!` %>%
rowSums %>%
is_greater_than(0) %>%
as.integer)
# hopex hopey hopez hopea hopeb dreamx dreamy dreamz dreama dreamb joyx joyy joyz joya joyb hope
#1 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 0
#2 1 1 4 3 2 3 5 4 5 2 5 NA 4 3 1 1
#3 2 NA 4 4 4 3 5 NA 5 5 4 NA 4 5 1 1
#4 4 3 NA 1 1 1 5 2 NA 5 1 2 1 1 1 1
#5 1 NA 4 NA NA 2 1 5 1 2 NA 3 1 2 5 1
Or with rowSums
df %>%
mutate(hope = +(rowSums(!is.na(select(., starts_with('hope'))))!= 0))
For multiple columns, we can create a function
f1 <- function(dat, colSubstr) {
dplyr::select(dat, starts_with(colSubstr)) %>%
is.na %>%
`!` %>%
rowSums %>%
is_greater_than(0) %>%
as.integer
}
df %>%
mutate(hope = f1(., 'hope'),
dream = f1(., 'dream'),
joy = f1(., 'joy'))
Or using base R
cbind(df, sapply(split.default(df, sub(".$", "", names(df))),
function(x) +(rowSums(!is.na(x)) != 0)))
If we want to subset columns
nm1 <- setdiff(names(df), "ID")
cbind(df, sapply(split.default(df[nm1], sub(".$", "", names(df[nm1]))),
function(x) +(rowSums(!is.na(x)) != 0)))
data
set.seed(24)
df <- as.data.frame(matrix(sample(c(NA, 1:5), 5 * 15, replace = TRUE),
ncol = 15, dimnames = list(NULL, paste0(rep(c("hope", "dream", "joy"),
each = 5), c('x', 'y', 'z', 'a', 'b')))))
df[1,] <- NA

Applying custom function to each row uses only first value of argument

I am trying to recode NA values to 0 in a subset of columns using the following dataset:
set.seed(1)
df <- data.frame(
id = c(1:10),
trials = sample(1:3, 10, replace = T),
t1 = c(sample(c(1:9, NA), 10)),
t2 = c(sample(c(1:7, rep(NA, 3)), 10)),
t3 = c(sample(c(1:5, rep(NA, 5)), 10))
)
Each row has a certain number of trials associated with it (between 1-3), specified by the trials column. columns t1-t3 represent scores for each trial.
The number of trials indicates the subset of columns in which NAs should be recoded to 0: NAs that are within the number of trials represent missing data, and should be recoded as 0, while NAs outside the number of trials are not meaningful, and should remain NAs. So, for a row where trials == 3, an NA in column t3 would be recoded as 0, but in a row where trials == 2, an NA in t3 would remain an NA.
So, I tried using this function:
replace0 <- function(x, num.sun) {
x[which(is.na(x[1:(num.sun + 2)]))] <- 0
return(x)
}
This works well for single vectors. When I try applying the same function to a data frame with apply(), though:
apply(df, 1, replace0, num.sun = df$trials)
I get a warning saying:
In 1:(num.sun + 2) :
numerical expression has 10 elements: only the first used
The result is that instead of having the value of num.sun change every row according to the value in trials, apply() simply uses the first value in the trials column for every single row. How could I apply the function so that the num.sun argument changes according to the value of df$trials?
Thanks!
Edit: as some have commented, the original example data had some non-NA scores that didn't make sense according to the trials column. Here's a corrected dataset:
df <- data.frame(
id = c(1:5),
trials = c(rep(1, 2), rep(2, 1), rep(3, 2)),
t1 = c(NA, 7, NA, 6, NA),
t2 = c(NA, NA, 3, 7, 12),
t3 = c(NA, NA, NA, 4, NA)
)
Another approach:
# create an index of the NA values
w <- which(is.na(df), arr.ind = TRUE)
# create an index with the max column by row where an NA is allowed to be replaced by a zero
m <- matrix(c(1:nrow(df), (df$trials + 2)), ncol = 2)
# subset 'w' such that only the NA's which fall in the scope of 'm' remain
i <- w[w[,2] <= m[,2][match(w[,1], m[,1])],]
# use 'i' to replace the allowed NA's with a zero
df[i] <- 0
which gives:
> df
id trials t1 t2 t3
1 1 1 3 NA 5
2 2 2 2 2 NA
3 3 2 6 6 4
4 4 3 0 1 2
5 5 1 5 NA NA
6 6 3 7 0 0
7 7 3 8 7 0
8 8 2 4 5 1
9 9 2 1 3 NA
10 10 1 9 4 3
You could easily wrap this in a function:
replace.NA.with.0 <- function(df) {
w <- which(is.na(df), arr.ind = TRUE)
m <- matrix(c(1:nrow(df), (df$trials + 2)), ncol = 2)
i <- w[w[,2] <= m[,2][match(w[,1], m[,1])],]
df[i] <- 0
return(df)
}
Now, using replace.NA.with.0(df) will produce the above result.
As noted by others, some rows (1, 3 & 10) have more values than trails. You could tackle that problem by rewriting the above function to:
replace.with.NA.or.0 <- function(df) {
w <- which(is.na(df), arr.ind = TRUE)
df[w] <- 0
v <- tapply(m[,2], m[,1], FUN = function(x) tail(x:5,-1))
ina <- matrix(as.integer(unlist(stack(v)[2:1])), ncol = 2)
df[ina] <- NA
return(df)
}
Now, using replace.with.NA.or.0(df) produces the following result:
id trials t1 t2 t3
1 1 1 3 NA NA
2 2 2 2 2 NA
3 3 2 6 6 NA
4 4 3 0 1 2
5 5 1 5 NA NA
6 6 3 7 0 0
7 7 3 8 7 0
8 8 2 4 5 NA
9 9 2 1 3 NA
10 10 1 9 NA NA
Here I just rewrite your function using double subsetting x[paste0('t',x['trials'])], which overcome the problem in the other two solutions with row 6
replace0 <- function(x){
#browser()
x_na <- x[paste0('t',x['trials'])]
if(is.na(x_na)){x[paste0('t',x['trials'])] <- 0}
return(x)
}
t(apply(df, 1, replace0))
id trials t1 t2 t3
[1,] 1 1 3 NA 5
[2,] 2 2 2 2 NA
[3,] 3 2 6 6 4
[4,] 4 3 NA 1 2
[5,] 5 1 5 NA NA
[6,] 6 3 7 NA 0
[7,] 7 3 8 7 0
[8,] 8 2 4 5 1
[9,] 9 2 1 3 NA
[10,] 10 1 9 4 3
Here is a way to do it:
x <- is.na(df)
df[x & t(apply(x, 1, cumsum)) > 3 - df$trials] <- 0
The output looks like this:
> df
id trials t1 t2 t3
1 1 1 3 NA 5
2 2 2 2 2 NA
3 3 2 6 6 4
4 4 3 0 1 2
5 5 1 5 NA NA
6 6 3 7 0 0
7 7 3 8 7 0
8 8 2 4 5 1
9 9 2 1 3 NA
10 10 1 9 4 3
> x <- is.na(df)
> df[x & t(apply(x, 1, cumsum)) > 3 - df$trials] <- 0
> df
id trials t1 t2 t3
1 1 1 3 NA 5
2 2 2 2 2 NA
3 3 2 6 6 4
4 4 3 0 1 2
5 5 1 5 NA NA
6 6 3 7 0 0
7 7 3 8 7 0
8 8 2 4 5 1
9 9 2 1 3 NA
10 10 1 9 4 3
Note: row 1/3/10, is problematic since there are more non-NA values than the trials.
Here's a tidyverse way, note that it doesn't give the same output as other solutions.
Your example data shows results for trials that "didn't happen", I assumed your real data doesn't.
library(tidyverse)
df %>%
nest(matches("^t\\d")) %>%
mutate(data = map2(data,trials,~mutate_all(.,replace_na,0) %>% select(.,1:.y))) %>%
unnest
# id trials t1 t2 t3
# 1 1 1 3 NA NA
# 2 2 2 2 2 NA
# 3 3 2 6 6 NA
# 4 4 3 0 1 2
# 5 5 1 5 NA NA
# 6 6 3 7 0 0
# 7 7 3 8 7 0
# 8 8 2 4 5 NA
# 9 9 2 1 3 NA
# 10 10 1 9 NA NA
Using the more commonly used gather strategy this would be:
df %>%
gather(k,v,matches("^t\\d")) %>%
arrange(id) %>%
group_by(id) %>%
slice(1:first(trials)) %>%
mutate_at("v",~replace(.,is.na(.),0)) %>%
spread(k,v)
# # A tibble: 10 x 5
# # Groups: id [10]
# id trials t1 t2 t3
# <int> <int> <dbl> <dbl> <dbl>
# 1 1 1 3 NA NA
# 2 2 2 2 2 NA
# 3 3 2 6 6 NA
# 4 4 3 0 1 2
# 5 5 1 5 NA NA
# 6 6 3 7 0 0
# 7 7 3 8 7 0
# 8 8 2 4 5 NA
# 9 9 2 1 3 NA
# 10 10 1 9 NA NA

R: Change values in a data frame according to values in another column of the same row

Let's say I have this kind of data frame:
df <- data.frame(
t=rep(seq(0,2),6),
no=rep(c(1,2,3,4,5,6),each=3),
value=rnorm(18),g=rep(c("nc","c1", NA),each=3)
)
t no value g
1 0 1 0.5022163 nc
2 1 1 0.5687227 nc
3 2 1 -0.2922622 nc
4 0 2 -0.3587089 c1
5 1 2 -0.9028012 c1
6 2 2 0.1926774 c1
7 0 3 0.6771236 NA
8 1 3 0.3752632 NA
9 2 3 0.2795892 NA
10 0 4 -0.4565521 nc
11 1 4 -0.1241807 nc
12 2 4 -1.2603695 nc
13 0 5 -0.6323118 c1
14 1 5 -0.6283850 c1
15 2 5 -0.2052317 c1
16 0 6 1.5996913 NA
17 1 6 -0.4802057 NA
18 2 6 -0.4255056 NA
I want to set the values in df$value to NA whenever there is NA in df$g (only in the same rows).
And similarly, set the values in df$value to NA, if df$no is, e.g., 1 or 5.
I was fooling around with for loops, but I could not get it right.
Any help will be much appreciated.
Thanks
With a for loop
for (i in 1:nrow(df)) {
if (df$no[i] == 1 | df$no[i] == 5 | is.na(df$g[i])) {
df$value[i] <- NA
}
}

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