7

我有一个data.frame与row.names测试中的一样。

test <-
c("Env_1990:trait_KPS", "Env_1990:trait_SPSM", "Env_1990:trait_TKW",
"Env_1990:trait_Yield", "Env_1991:trait_KPS", "Env_1991:trait_SPSM",
"Env_1991:trait_TKW", "Env_1991:trait_Yield", "Env_1992:trait_KPS",
"Env_1992:trait_SPSM", "Env_1992:trait_TKW", "Env_1992:trait_Yield",
"Env_1993:trait_KPS", "Env_1993:trait_SPSM", "Env_1993:trait_TKW",
"Env_1993:trait_Yield", "Env_1994:trait_KPS", "Env_1994:trait_SPSM",
"Env_1994:trait_TKW", "Env_1994:trait_Yield", "Env_1995:trait_KPS",
"Env_1995:trait_SPSM", "Env_1995:trait_TKW", "Env_1995:trait_Yield",
"Gen_B88:Env_1990:trait_KPS", "Gen_B88:Env_1990:trait_SPSM",
"Gen_B88:Env_1990:trait_TKW", "Gen_B88:Env_1990:trait_Yield",
"Gen_B88:Env_1991:trait_KPS", "Gen_B88:Env_1991:trait_SPSM",
"Gen_B88:Env_1991:trait_TKW", "Gen_B88:Env_1991:trait_Yield",
"Gen_B88:Env_1992:trait_KPS", "Gen_B88:Env_1992:trait_SPSM",
"Gen_B88:Env_1992:trait_TKW", "Gen_B88:Env_1992:trait_Yield",
"Gen_B88:Env_1993:trait_KPS", "Gen_B88:Env_1993:trait_SPSM",
"Gen_B88:Env_1993:trait_TKW", "Gen_B88:Env_1993:trait_Yield")

我只想选择那些以Env_. 我试过这段代码R

grep(pattern="[Env_]", x=test).

这段代码给了我所有的行，因为Env_出现在每一行的名称中。我想知道如何选择仅以Env_. 在此先感谢您的帮助。

4

1 回答 1

14

您想为行/字符串^的开头添加字符：

> grep("^Env_", test)
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
> grep("^Env_", test, value = TRUE)
 [1] "Env_1990:trait_KPS"   "Env_1990:trait_SPSM"  "Env_1990:trait_TKW"  
 [4] "Env_1990:trait_Yield" "Env_1991:trait_KPS"   "Env_1991:trait_SPSM" 
 [7] "Env_1991:trait_TKW"   "Env_1991:trait_Yield" "Env_1992:trait_KPS"  
[10] "Env_1992:trait_SPSM"  "Env_1992:trait_TKW"   "Env_1992:trait_Yield"
[13] "Env_1993:trait_KPS"   "Env_1993:trait_SPSM"  "Env_1993:trait_TKW"  
[16] "Env_1993:trait_Yield" "Env_1994:trait_KPS"   "Env_1994:trait_SPSM" 
[19] "Env_1994:trait_TKW"   "Env_1994:trait_Yield" "Env_1995:trait_KPS"  
[22] "Env_1995:trait_SPSM"  "Env_1995:trait_TKW"   "Env_1995:trait_Yield"
于 2012-04-09T00:36:09.087 回答