从向量中删除NA值

How can I remove NA values from a vector?

如何从向量中去除NA值?

I have a huge vector which has a couple of NA values, and I'm trying to find the max value in that vector (the vector is all numbers), but I can't do this because of the NA values.

我有一个巨大的向量，它有两个NA值，我试图找到这个向量的最大值(这个向量是所有数字)，但是我不能这么做，因为这个值是NA。

How can I remove the NA values so that I can compute the max?

如何去掉NA的值以便计算最大值?

5 个解决方案

#1

196

Trying ?max, you'll see that it actually has a na.rm = argument, set by default to FALSE. (That's the common default for many other R functions, including sum(), mean(), etc.)

试试?麦克斯，你会发现它其实有个na。参数，默认设置为FALSE。(这是许多其他R函数的常见默认值，包括sum()、mean()等)。

Setting na.rm=TRUE does just what you're asking for:

设置na。rm=TRUE就是你想要的:

d <- c(1, 100, NA, 10)
max(d, na.rm=TRUE)

If you do want to remove all of the NAs, use this idiom instead:

如果您确实想删除所有的NAs，请使用这个习语:

d <- d[!is.na(d)]

A final note: Other functions (e.g. table(), lm(), and sort()) have NA-related arguments that use different names (and offer different options). So if NA's cause you problems in a function call, it's worth checking for a built-in solution among the function's arguments. I've found there's usually one already there.

最后要注意的是:其他函数(例如表()、lm()和sort())具有使用不同名称(并提供不同选项)的与na相关的参数。因此，如果NA在函数调用中出现问题，那么在函数的参数中检查内置的解决方案是值得的。我发现通常已经有一个了。

#2

The na.omit function is what a lot of the regression routines use internally:

na。省略函数是许多回归例程内部使用的函数:

vec <- 1:1000
vec[runif(200, 1, 1000)] <- NA
max(vec)
#[1] NA
max( na.omit(vec) )
#[1] 1000

#3

?max shows you that there is an extra parameter na.rm that you can set to TRUE.

max向你展示了一个额外的参数na。可以设置为TRUE。

Apart from that, if you really want to remove the NAs, just use something like:

除此之外，如果您真的想删除NAs，只需使用以下内容:

myvec[!is.na(myvec)]

#4

You can call max(vector, na.rm = TRUE). More generally, you can use the na.omit() function.

你可以叫max(向量，na)rm = TRUE)。更一般地说，您可以使用na.omit()函数。

#5

Just in case someone new to R wants a simplified answer to the original question

以防有人对R有新想法，想要原始问题的简化答案

How can I remove NA values from a vector?

如何从向量中去除NA值?

Here it is:

这里是:

Assume you have a vector foo as follows:

假设有一个向量foo，如下所示:

foo = c(1:10, NA, 20:30)

running length(foo) gives 22.

运行长度(foo)为22。

nona_foo = foo[!is.na(foo)]

length(nona_foo) is 21, because the NA values have been removed.

长度(nona_foo)是21，因为NA值已经被删除。

Remember is.na(foo) returns a boolean matrix, so indexing foo with the opposite of this value will give you all the elements which are not NA.

记住，is.na(foo)返回一个布尔矩阵，因此，与这个值相反的foo将给出所有非NA的元素。

#1

196