如何从使用write.table创建的CSV文件中删除尾随空格或换行符？ [英] How to remove trailing blanks or linebreaks from CSV file created with write.table?

问题描述

我想将一个数据帧从R写入CSV文件。考虑下面的玩具示例

  df  df [ 
 
 write.table（t（df），file =path to CSV / test.csv，sep =），col.names = F，sep =，，quote = F ）
  

test.csv 如下

  ID，1,2,3 
 X，a，b，c 
 Y， 1，2，NA 
  

乍一看，这正是我需要的，但不能在上面的代码插入中看到的是，在最后一行中的 NA 之后，有另一个换行符。然而，当我将 test.csv 传递给网站上的Javascript图表时，后面的linebreak会导致麻烦。

有没有办法避免R中的最后一次换行？

解决方案

这是一个有点复杂，但获得你想要的结果：

  zz<  -  textConnection（foo，w）
 write.table（t（df），file = zz，col.names = ，，quote = F）
 close（zz）
 foo 
＃[1]ID，1,2,3X，a，b，c 1，2，NA
 cat（paste（foo，collapse ='\\\
'），file ='test.csv'，sep =''）
  / pre> 
 
 
你最终只能在前两个数据行之后有换行符的文件。
 
I want to write a data frame from R into a CSV file. Consider the following toy example
df <- data.frame(ID = c(1,2,3), X = c("a", "b", "c"), Y = c(1,2,NA))
df[which(is.na(df[,"Y"])), 1]

write.table(t(df), file = "path to CSV/test.csv", sep = ""), col.names=F, sep=",", quote=F)
The output in test.csvlooks as follows
ID,1,2,3
X,a,b,c
Y, 1, 2,NA
At first glance, this is exactly as I need it, BUT what cannot be seen in the code insertion above is that after the NA in the last line, there is another linebreak. When I pass test.csv to a Javascript chart on a website, however, the trailing linebreak causes trouble. 

Is there a way to avoid this final linebreak within R? 
解决方案
This is a little convoluted, but obtains your desired result:
zz <- textConnection("foo", "w")
write.table(t(df), file = zz, col.names=F, sep=",", quote=F)
close(zz)
foo
# [1] "ID,1,2,3"   "X,a,b,c"    "Y, 1, 2,NA"
cat(paste(foo, collapse='\n'), file = 'test.csv', sep='')
You should end up with a file that has newline character after only the first two data rows.

                        
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