导入read.csv/read.xlsx时将NA值插入数据框空白单元格 [英] Insert NA values into dataframe blank cells when importing read.csv/read.xlsx
本文介绍了导入read.csv/read.xlsx时将NA值插入数据框空白单元格的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
随附的屏幕截图显示了我刚刚从excel文件导入到R中的数据框的一部分.在空白的单元格中,我需要插入"NA".如何将NA插入任何空白单元格中(而将已填充的单元格留空)?
The attached screenshot shows part of a dataframe which I have just imported into R from an excel file. In the cells which are blank, I need to insert 'NA'. How can I insert NA into any cell which is blank (whilst leaving the already populated cells alone)?
推荐答案
更好的问题是如何将其读入R,以便丢失的单元格已经是NA
s.
The better question is how can I read it into R so the missing cells will already be NA
s.
也许您使用过这样的东西:
Maybe you used something like this:
read.csv(file, header=FALSE, strip.white = TRUE, sep=",")
在以下列方式阅读时,指定NA
字符串:
Specify the NA
strings like this when you read it in:
read.csv(file, header=FALSE, strip.white = TRUE, sep=",",
na.strings= c("999", "NA", " ", ""))
实际回答您的问题.这种方法可能有效:
to actually answer your question. This approach could work:
#making fake data on a Saturday morning
dat <- data.frame(matrix(sample(c("", LETTERS[1:4]), 200,
replace=T, c(.6, rep(.1, 4))), 20))
#function to replace blanks with missing
blank2na <- function(x){
z <- gsub("\\s+", "", x) #make sure it's "" and not " " etc
x[z==""] <- NA
return(x)
}
#apply that function
data.frame(sapply(dat, blank2na))
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