用NA值替换负值

Question

我NA在表中有正,负和值,我需要用值替换负值NA.正数和NA值应保持在表中.我的数据集类似于下面的数据集:

NO. q
1   NA
2   NA
3   -133.6105198
4   -119.6991209
5   28.84460104
6   66.05345087
7   84.7058947
8   -134.4522694
9   NA
10  NA
11  73.20465643
12  -69.90723514
13  NA
14  69.70833003
15  65.27859906

我试过这个:

if (q>0) {
    q=NA
} else {
    q=q
}

Answer 1

你可以尝试

df1$q1 <- NA^(df1$q <0) * df1$q
df1
#   NO.          q       q1
#1    1         NA       NA
#2    2         NA       NA
#3    3 -133.61052       NA
#4    4 -119.69912       NA
#5    5   28.84460 28.84460
#6    6   66.05345 66.05345
#7    7   84.70589 84.70589
#8    8 -134.45227       NA
#9    9         NA       NA
#10  10         NA       NA
#11  11   73.20466 73.20466
#12  12  -69.90724       NA 
#13  13         NA       NA
#14  14   69.70833 69.70833
#15  15   65.27860 65.27860

或者使用ifelse

 with(df1, ifelse(q < 0, NA, q))

或者

 is.na(df1$q) <- df1$q < 0

Answer 2

或使用replace：

> df$q2 <- replace(df$q, which(df$q < 0), NA)
> df
   NO.          q       q2
1    1         NA       NA
2    2         NA       NA
3    3 -133.61052       NA
4    4 -119.69912       NA
5    5   28.84460 28.84460
6    6   66.05345 66.05345
7    7   84.70589 84.70589
8    8 -134.45227       NA
9    9         NA       NA
10  10         NA       NA
11  11   73.20466 73.20466
12  12  -69.90724       NA
13  13         NA       NA
14  14   69.70833 69.70833
15  15   65.27860 65.27860

或与data.table一起使用：

library(data.table)
setDT(df)[q < 0, q := NA]

或在dplyr管道中替换：

library(dplyr)
df %>% mutate(q = replace(q, which(q<0), NA))

Answer 3

你可以试试这个:

sample <- c(1, -2, NA)
sample[sample < 0] <- NA
sample
[1]  1 NA NA

或者,如果你正在使用a data.frame(假设它被称为df):

df$q[df$q < 0] <- NA