从数据帧中删除特定行 [英] Removing specific rows from a dataframe

问题描述

我有一个数据框架，例如：

I have a data frame e.g.:

sub   day
1      1
1      2
1      3
1      4
2      1
2      2
2      3
2      4
3      1
3      2
3      3
3      4

我想删除可以识别的特定行子和日的组合。
例如，我想删除行，其中sub ='1'和day ='2'，sub = 3和day ='4'。我该怎么做？
我意识到我可以指定行号，但是这需要应用到一个巨大的数据帧，这将是繁琐的，每一行都要经历ID和ID。

and I would like to remove specific rows that can be identified by the combination of sub and day. For example say I wanted to remove rows where sub='1' and day='2' and sub=3 and day='4'. How could I do this? I realise that I could specify the row numbers, but this needs to be applied to a huge dataframe which would be tedious to go through and ID each row.

推荐答案

DF[ ! DF$sub %in% c(1, 2, 3), ]   # note the ! (negation)

或者如果sub是使用引号建议的因素：

Or if sub is a factor as suggested by your use of quotes:

DF[ ! DF$sub %in% c("1", "2", "3"), ]

也可以使用子集：

subset(DF,  ! sub %in% c("1", "2", "3") )

（我认同使用哪个在Dirk的答案中使用[即使有人声称它不需要。）

(And I endorse the use of which in Dirk's answer when using "[" even though some claim it is not needed.)

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