根據另一個數據框的行的一個數據框的子集列

Question

我想根據另一個數據框的行對其某些列進行子集劃分。所以這兩個數據幀，如下所示：

df1 <- structure(list(ID = structure(c(3L, 1L, 2L, 5L, 4L), .Label = c("cg08", "cg09", "cg29", "cg36", "cg65"), class = "factor"), chr = c(16L, 3L, 3L, 1L, 8L), gene = c(534L, 376L, 171L, 911L, 422L), GS12 = c(0.15, 0.87, 0.6, 0.1, 0.72), GS32 = c(0.44, 0.93, 0.92, 0.07, 0.91),  GS56 = c(0.46, 0.92, 0.62, 0.06, 0.87), GS87 = c(0.79, 0.93,  0.86, 0.08, 0.88)), .Names = c("ID", "chr", "gene", "GS12", "GS32", "GS56", "GS87"), class = "data.frame", row.names = c("1", "2", "3", "4", "5")) 
df2 <- structure(list(samples = structure(c(1L, 2L, 4L, 3L, 6L, 5L), .Label = c("GS32", "GS33", "GS55", "GS56", "GS68", "GS87"), class = "factor"), ID2 = structure(c(1L, 6L, 3L, 4L, 5L, 2L), .Label = c("GM1", "GM10", "GM17", "GM18", "GM19", "GM7"), class = "factor")), .Names = c("samples", "ID2"), class = "data.frame", row.names = c(NA, -6L)) 

數據：

df1: 
      ID  chr gene GS12  GS32  GS56  GS87 
     1 cg29  16 534  0.15  0.44  0.46  0.79 
     2 cg08   3 376  0.87  0.93  0.92  0.93 
     3 cg09   3 171  0.60  0.92  0.62  0.86 
     4 cg65   1 911  0.10  0.07  0.06  0.08 
     5 cg36   8 422  0.72  0.91  0.87  0.88 
df2: 

samples ID2  
GS32 GM1   
GS33 GM7   
GS56 GM17   
GS55 GM18   
GS87 GM19   
GS68 GM10   

我想子集從DF1（同時保持在最終輸出的所有行），在常見的所有列簡而言之，我想根據另一個數據框的行對一個數據框的列進行子集劃分，是否有任何功能可以做到這一點？

Answer 1

輸入數據：

df1 <- structure(list(ID = structure(c(3L, 1L, 2L, 5L, 4L), .Label = c("cg08", "cg09", "cg29", "cg36", "cg65"), class = "factor"), chr = c(16L, 3L, 3L, 1L, 8L), gene = c(534L, 376L, 171L, 911L, 422L), GS12 = c(0.15, 0.87, 0.6, 0.1, 0.72), GS32 = c(0.44, 0.93, 0.92, 0.07, 0.91),  GS56 = c(0.46, 0.92, 0.62, 0.06, 0.87), GS87 = c(0.79, 0.93,  0.86, 0.08, 0.88)), .Names = c("ID", "chr", "gene", "GS12", "GS32", "GS56", "GS87"), class = "data.frame", row.names = c("1", "2", "3", "4", "5")) 
df2 <- structure(list(samples = structure(c(1L, 2L, 4L, 3L, 6L, 5L), .Label = c("GS32", "GS33", "GS55", "GS56", "GS68", "GS87"), class = "factor"), ID2 = structure(c(1L, 6L, 3L, 4L, 5L, 2L), .Label = c("GM1", "GM10", "GM17", "GM18", "GM19", "GM7"), class = "factor")), .Names = c("samples", "ID2"), class = "data.frame", row.names = c(NA, -6L)) 

我相信你所要求的是以下幾點：

df1[colnames(df1) %in% df2$samples] 
# GS32 GS56 GS87 
#1 0.44 0.46 0.79 
#2 0.93 0.92 0.93 
#3 0.92 0.62 0.86 
#4 0.07 0.06 0.08 
#5 0.91 0.87 0.88 

要檢查發生DF2的樣本中DF1列名。
不過，我想你也需要在你的輸出數據幀的ID，染色體和基因，這是可以做到以下幾點：

df1[c(1:3, colnames(df1) %in% df2$samples)] 
# ID chr gene ID.1 ID.2 ID.3 
#1 cg29 16 534 cg29 cg29 cg29 
#2 cg08 3 376 cg08 cg08 cg08 
#3 cg09 3 171 cg09 cg09 cg09 
#4 cg65 1 911 cg65 cg65 cg65 
#5 cg36 8 422 cg36 cg36 cg36 

---

如果要強制列順序是在與以前相同的順序，使用match而不是%in%。 match需要至少兩個變量，第一個是目標矢量，第二個是它需要分類到的數據幀/矢量。

df1[,c(1:3,na.omit(match(df2$samples, colnames(df1))))] 
# ID chr gene GS32 GS56 GS87 
#1 cg29 16 534 0.44 0.46 0.79 
#2 cg08 3 376 0.93 0.92 0.93 
#3 cg09 3 171 0.92 0.62 0.86 
#4 cg65 1 911 0.07 0.06 0.08 
#5 cg36 8 422 0.91 0.87 0.88