如何在R中再应用一个for循环？

Question

我想写一个R风格的for循环(？)若要避免下列重复代码，请执行以下操作。

df1$fusion <- apply(df1[, cols], 1, paste, collapse = "-" )
df2$fusion <- apply(df2[, cols], 1, paste, collapse = "-" )
df3$fusion <- apply(df3[, cols], 1, paste, collapse = "-" )
df4$fusion <- apply(df4[, cols], 1, paste, collapse = "-" )
df5$fusion <- apply(df5[, cols], 1, paste, collapse = "-" )
df6$fusion <- apply(df6[, cols], 1, paste, collapse = "-" )
df7$fusion <- apply(df7[, cols], 1, paste, collapse = "-" )
df8$fusion <- apply(df8[, cols], 1, paste, collapse = "-" )
df9$fusion <- apply(df9[, cols], 1, paste, collapse = "-" )
df10$fusion <- apply(df10[, cols], 1, paste, collapse = "-" )
df11$fusion <- apply(df11[, cols], 1, paste, collapse = "-" )
df12$fusion <- apply(df12[, cols], 1, paste, collapse = "-" )

我该怎么做呢？类似于shell脚本风格的东西？

df_ls=("df1 df2 df3 df4 df5 df6 df7 df8 df9 df10 df11 df12")

for i in $df_ls
do
${i}$fusion <- apply(${i}[, cols], 1, paste, collapse = "-" )
done

Answer 1

有单子。例如在你的情况下。

list_df_general <- list(df, df2,...,df12) # load your date frames
lista_new <- list() # list empty
for(i in 12){
  lista_new[[i]] <- apply(lista_df_general[[i]][, cols], 1, paste, collapse = "-" )
}

对于浏览器内部列表，您应该执行以下操作

list_new[[1]] or list_new[[2]] with 3,4,...,12.

Answer 2

你可以用这样的方法

my_Fun <- function(df, cols)
{
  df$fusion <- apply(df[, cols], 1, paste, collapse = "-" )
}

for(i in 1 : 12)
{
  variable_Name <- paste0("df", i)
  assign(x = variable_Name, value = my_Fun(df = get(x = variable_Name), cols = cols))
}

Answer 3

您可以在数据文件列表中使用lapply和apply的组合。这将返回数据格式的列表。

df_ls <- mget(paste0("df", 1:12))

lapply(df_ls, function(x) {x$fusion <- apply(x[, cols], 1, paste, collapse = "-" ); x})