How to avoid space while reading .txt file

问题

I am trying to read a file which has a column of + and - but apparently associated with a space after that. In anyway I read (read.csv or read.table or read_excel that file I pick up the space after.

For example:

df = data.frame(x = c('a', 'b', 'c'), y = c('+ ', "- ", "+ "))
df
  x  y
1 a + 
2 b - 
3 c + 

Now, is there a way to specifically instruct not to pick up space after the value in read.csv or read_excel

Or is there a way to clean up the spaces after reading into a dataframe?

来源：https://stackoverflow.com/questions/43433491/how-to-avoid-space-while-reading-txt-file