Removing NA columns in xts

问题

I have an xts in the following format

                   a        b     c        d       e        f   ......
2011-01-03         11.40    NA    23.12    0.23    123.11   NA  ......
2011-01-04         11.49    NA    23.15    1.11    111.11   NA  ......
2011-01-05         NA       NA    23.11    1.23    142.32   NA  ......
2011-01-06         11.64    NA    39.01    NA      124.21   NA  ......
2011-01-07         13.84    NA    12.12    1.53    152.12   NA  ......

Is there a function I can apply to generate a new xts or data.frame missing the columns containing only NA?

The position of the columns with the NAs isn't static so just removing those columns by name or position isn't possible

回答1:

Supose DF is your data.frame

 DF [, -which(sapply(DF, function(x) sum(is.na(x)))==nrow(DF))]
               a     c    d      e
2011-01-03 11.40 23.12 0.23 123.11
2011-01-04 11.49 23.15 1.11 111.11
2011-01-05    NA 23.11 1.23 142.32
2011-01-06 11.64 39.01   NA 124.21
2011-01-07 13.84 12.12 1.53 152.12

回答2:

@Jiber's solution works, but might give you unexpected results if there are no columns with all NA. For example:

# sample data
library(xts)
data(sample_matrix)
x <- as.xts(sample_matrix)

# Jiber's solution, when no columns have all missing values
DF <- as.data.frame(x)
DF[, -which(sapply(DF, function(x) sum(is.na(x)))==nrow(DF))]
# data frame with 0 columns and 180 rows

Here's a solution that works whether or not there are columns that have all missing values:

y <- x[,apply(!is.na(x), 2, all)]
x$High <- NA
x$Close <- NA
z <- x[,apply(!is.na(x), 2, all)]

回答3:

Try this:

dataframe[,-which(apply(is.na(dataframe), 2, all))]

回答4:

This seems simpler:

DF[, colSums(is.na(DF)) < nrow(DF)]

来源：https://stackoverflow.com/questions/13098888/removing-na-columns-in-xts

标签

xts

quantmod