相关疑难解决方法(0)

我刚在剧本中发现了这个警告,有点奇怪.

# Warning message:
# In rbindlist(list(DT.1, DT.2)) : NAs introduced by coercion

观察1:这是一个可重复的例子:

require(data.table)
DT.1 <- data.table(x = letters[1:5], y = 6:10)
DT.2 <- data.table(x = LETTERS[1:5], y = 11:15)

# works fine
rbindlist(list(DT.1, DT.2))
#     x  y
#  1: a  6
#  2: b  7
#  3: c  8
#  4: d  9
#  5: e 10
#  6: A 11
#  7: B 12
#  8: C 13
#  9: D 14
# 10: E 15 …