根据字符串模式和ifelse的存在创建列 [英] Create column based on presence of string pattern and ifelse
问题描述
如果模式匹配,我想用两个值之一填充新列.
I would like to fill in a new column with one of two values if a pattern is matched.
这是我的数据框:
df <- structure(list(loc_01 = c("apis", "indu", "isro", "miss", "non_apis",
"non_indu", "non_isro", "non_miss", "non_piro", "non_sacn", "non_slbe",
"non_voya", "piro", "sacn", "slbe", "voya"), loc01_land = c(165730500,
62101800, 540687600, 161140500, 1694590200, 1459707300, 1025051400,
1419866100, 2037064500, 2204629200, 1918840500, 886299300, 264726000,
321003900, 241292700, 530532000)), class = "data.frame", row.names = c(NA,
-16L), .Names = c("loc_01", "loc01_land"))
看起来像这样...
loc_01 loc01_land
1 apis 165730500
2 indu 62101800
3 isro 540687600
4 miss 161140500
5 non_apis 1694590200
6 non_indu 1459707300
7 non_isro 1025051400
8 non_miss 1419866100
9 non_piro 2037064500
10 non_sacn 2204629200
11 non_slbe 1918840500
12 non_voya 886299300
13 piro 264726000
14 sacn 321003900
15 slbe 241292700
16 voya 530532000
我想在df
中添加一列,称为"loc_01".如果loc_01包含 non ,则返回'outside';如果loc_01不包含 non ,则返回'inside'.这是我的ifelse语句,但我遗漏了一些东西,因为它仅返回false
值.
I would like to add a column to df
, called 'loc_01'. If loc_01 contains non, then return 'outside', if it does not contain non, then return 'inside'. This is my ifelse statement, but I'm missing something because it only returns the false
value.
df$loc01 <- ifelse(df$loc_01 == "non", 'outside', 'inside')
产生的df ...
loc_01 loc01_land loc01
1 apis 165730500 inside
2 indu 62101800 inside
3 isro 540687600 inside
4 miss 161140500 inside
5 non_apis 1694590200 inside
6 non_indu 1459707300 inside
7 non_isro 1025051400 inside
8 non_miss 1419866100 inside
9 non_piro 2037064500 inside
10 non_sacn 2204629200 inside
11 non_slbe 1918840500 inside
12 non_voya 886299300 inside
13 piro 264726000 inside
14 sacn 321003900 inside
15 slbe 241292700 inside
16 voya 530532000 inside
谢谢 -al
推荐答案
要检查字符串是否包含某个子字符串,不能使用==
,因为它执行的是完全匹配(即仅当字符串恰好是"non"时才返回true.
您可以使用例如grepl
函数(属于 grep系列功能),执行模式匹配:
To check if a string contains a certain substring, you can't use ==
because it performs an exact matching (i.e. returns true only if the string is exactly "non").
You could use for example grepl
function (belonging to grep family of functions) that performs a pattern matching:
df$loc01 <- ifelse(grepl("non",df$loc_01),'outside','inside')
结果:
> df
loc_01 loc01_land loc01
1 apis 165730500 inside
2 indu 62101800 inside
3 isro 540687600 inside
4 miss 161140500 inside
5 non_apis 1694590200 outside
6 non_indu 1459707300 outside
7 non_isro 1025051400 outside
8 non_miss 1419866100 outside
9 non_piro 2037064500 outside
10 non_sacn 2204629200 outside
11 non_slbe 1918840500 outside
12 non_voya 886299300 outside
13 piro 264726000 inside
14 sacn 321003900 inside
15 slbe 241292700 inside
16 voya 530532000 inside
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