问题
I've seen plenty of discussion on using paste and paste0 to concatenate two strings in r. However, this does not appear to be working for two string variables. I have a data frame that looks like the following.
series_id year period value footnote_codes
1 LASBS260000000000003 1983 M01 15.1
2 LASBS260000000000003 1983 M02 15.0
3 LASBS260000000000003 1983 M03 14.8
4 LASBS260000000000003 1983 M04 14.6
I wish to combine the year variable to the period variable to generate a new variable in the data frame called observation. The data frame is called data and I tried the following paste command based on research of similar inquiries.
data$obs<-paste0(toString(data$year),toString(data$period))
data$obs<-paste(toString(data$year),toString(data$period),sep="")
This is not giving me the expected single variable taking on values "1983M01"... as expected. Any thoughts would be greatly appreciated.
Steve
回答1:
Following works:
> apply(ddf,1 ,function(x) paste0(toString(x[2]), toString(x[3])))
[1] "1983M01" "1983M02" "1983M03" "1983M04"
>
> apply(ddf,1 ,function(x) paste(toString(x[2]), toString(x[3])))
[1] "1983 M01" "1983 M02" "1983 M03" "1983 M04"
toString(ddf$year) binds entire column in one string:
> toString(ddf$year)
[1] "1983, 1983, 1983, 1983"
>
> toString(ddf$period)
[1] "M01, M02, M03, M04"
>
> paste(toString(ddf$year), toString(ddf$period))
[1] "1983, 1983, 1983, 1983 M01, M02, M03, M04"
回答2:
I encountered the problem mentioned above: I wanted to concatenate "year" (numeric) with a string variable. As a solution, I used "as.character" instead of "toString" and then concatenated the variables using "paste0". This worked for me. For example,
df$c<-paste0(as.character(df$a)," ", as.character(df$b))
I know this is an old post. Hoping this helps some other users in a similar situation.
来源：https://stackoverflow.com/questions/26321702/concatenating-two-string-variables-in-r