sparklyr更改所有的列名火花數據幀

Question

我打算改變這一切的列名。當前的重命名或選擇操作太勞頓。我不知道是否有人有更好的解決方案。示例如下：

df <- data.frame(oldname1 = LETTERS, oldname2 = 1,...oldname200 = "APPLE") 
df_tbl <- copy_to(sc,df,"df") 
newnamelist <- paste("Name", 1:200, sep ="_") 

如何將newnamelist指定爲新的colnames？也許我不能做這樣的：

df_new <- df_tbl %>% dplyr::select(Name_1 = oldname1, Name_2 = oldname2,....) 

Answer 1

您可以使用select_與.dots：

df <- copy_to(sc, iris) 

newnames <- paste("Name", 1:5, sep="_") 

df %>% select_(.dots=setNames(colnames(df), newnames)) 

# Source: lazy query [?? x 5] 
# Database: spark_connection 
    Name_1 Name_2 Name_3 Name_4 Name_5 
    <dbl> <dbl> <dbl> <dbl> <chr> 
1 5.1 3.5 1.4 0.2 setosa 
2 4.9 3.0 1.4 0.2 setosa 
3 4.7 3.2 1.3 0.2 setosa 
4 4.6 3.1 1.5 0.2 setosa 
5 5.0 3.6 1.4 0.2 setosa 
6 5.4 3.9 1.7 0.4 setosa 
7 4.6 3.4 1.4 0.3 setosa 
8 5.0 3.4 1.5 0.2 setosa 
9 4.4 2.9 1.4 0.2 setosa 
10 4.9 3.1 1.5 0.1 setosa 

你也可以用select!!!：

library(rlang) 
library(purrr) 

df %>% select(!!! setNames(map(colnames(df), parse_quosure), newnames)) 

# Source: lazy query [?? x 5] 
# Database: spark_connection 
    Name_1 Name_2 Name_3 Name_4 Name_5 
    <dbl> <dbl> <dbl> <dbl> <chr> 
1 5.1 3.5 1.4 0.2 setosa 
2 4.9 3.0 1.4 0.2 setosa 
3 4.7 3.2 1.3 0.2 setosa 
4 4.6 3.1 1.5 0.2 setosa 
5 5.0 3.6 1.4 0.2 setosa 
6 5.4 3.9 1.7 0.4 setosa 
7 4.6 3.4 1.4 0.3 setosa 
8 5.0 3.4 1.5 0.2 setosa 
9 4.4 2.9 1.4 0.2 setosa 
10 4.9 3.1 1.5 0.1 setosa 
# ... with more rows