[英]R “Error: unexpected symbol in if”
For the life of me, I can't find an answer online to my very basic problem trying to execute an if
statement. 在我的一生中,我无法在线上尝试执行if
语句的最基本问题找到答案。 Any help greatly appreciated. 任何帮助,不胜感激。
data: 数据:
Id,mo.year,
123,201102
436,201101
129,201302
(Both variables are character) (两个变量都是字符)
Code: 码:
if(data$mo.year IN('201101','201102')) {data$year=1}
Results in: 结果是:
Error: unexpected symbol in "if (data$mo.year IN"
if(data$mo.year IN('201201','201202')) {data$year=2}
if(data$mo.year IN('201301','201302')) {data$year=3}
Yields same errors. 产生相同的错误。
Suggestions as to what I'm missing? 关于我所缺少的建议?
Thanks! 谢谢!
It looks like you just need ifelse
, the vectorized version of an if
statement: 看起来您只需要ifelse
,即if
语句的向量化版本:
Df <- data.frame(
Id=c('123','436','129'),
mo.year=c('201102','201101','201302'),
stringsAsFactors=FALSE)
##
Df$year <- ifelse(
Df$mo.year %in% c('201101','201102'),
1,
ifelse(
Df$mo.year %in% c('201201','201202'),
2,3))
##
> Df
Id mo.year year
1 123 201102 1
2 436 201101 1
3 129 201302 3
Assuming you are just using the fourth digit of the mo.year
column to generate your value, you could also do something like this, which is a little more concise: 假设您只是使用mo.year
列的第四位数字来生成您的值,那么您还可以执行以下操作,这更加简洁:
Df$year <- as.numeric(
gsub(
"(201)(\\d)(\\d+)","\\2",Df$mo.year))
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