按组比例表

Question

按组比例表

3

我有一个数据框，结构如下：

location               gender        15.19     20.30      31.40      41.64      65.
New York                Female          2         41         13         19        1
New York                  Male          1         23         15         17        2
San Francisco           Female          1         27         14         14        3
San Francisco             Male          4         24         14         10        1
Mexico City             Female          1         40         26         11        3
Mexico City               Male          4         23         35          8        3
Paris                   Female          2         12         10          6        0
Paris                     Male          1         20         13         11        1

我需要将其转换为比例表，每个单元格代表其所在城市的两行的比例。这是一种解决方案，但是否有更简单的方法可以用于多列（并且只是转换它们而不生成新列）？

编辑正确的输出应该将每个单元格作为该城市所有单元格的比例给出，因此共享位置“纽约”的所有单元格将加起来为1，共享位置“旧金山”的所有单元格也将加起来为1，等等。

 location             gender        15.19     20.30      31.40      41.64        65.
 New York             Female          .01       .31        .1         .14        .01
 New York               Male          .01       .17       .11         .13        .02

- Kasey

1

请问您能展示一下您所期望的输出的例子吗？ - Hack-R

1个回答

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- Sathish · Accepted Answer

library("data.table")
selected_cols <- colnames(df)[3:7]
setDT(df)[, prop.table(.SD), by = location, .SDcols = selected_cols]

#         location      X15.19    X20.30     X31.40     X41.64        X65.
# 1:      New York 0.014925373 0.3059701 0.09701493 0.14179104 0.007462687
# 2:      New York 0.007462687 0.1716418 0.11194030 0.12686567 0.014925373
# 3: San Francisco 0.008928571 0.2410714 0.12500000 0.12500000 0.026785714
# 4: San Francisco 0.035714286 0.2142857 0.12500000 0.08928571 0.008928571
# 5:   Mexico City 0.006493506 0.2597403 0.16883117 0.07142857 0.019480519
# 6:   Mexico City 0.025974026 0.1493506 0.22727273 0.05194805 0.019480519
# 7:         Paris 0.026315789 0.1578947 0.13157895 0.07894737 0.000000000
# 8:         Paris 0.013157895 0.2631579 0.17105263 0.14473684 0.013157895

验证结果：每个城市是否总和为1

a1 <- setDT(df)[, prop.table(.SD), by = location, .SDcols = selected_cols]
sum(subset(a1, location == "New York", select = selected_cols))
# [1] 1

然后性别列可以与a1结合。

do.call(cbind, list(gender = df$gender, a1))

数据:

dput(df)
structure(list(location = c("New York", "New York", "San Francisco", 
"San Francisco", "Mexico City", "Mexico City", "Paris", "Paris"
), gender = c("Female", "Male", "Female", "Male", "Female", "Male", 
"Female", "Male"), X15.19 = c(2L, 1L, 1L, 4L, 1L, 4L, 2L, 1L), 
    X20.30 = c(41L, 23L, 27L, 24L, 40L, 23L, 12L, 20L), X31.40 = c(13L, 
    15L, 14L, 14L, 26L, 35L, 10L, 13L), X41.64 = c(19L, 17L, 
    14L, 10L, 11L, 8L, 6L, 11L), X65. = c(1L, 2L, 3L, 1L, 3L, 
    3L, 0L, 1L)), .Names = c("location", "gender", "X15.19", 
"X20.30", "X31.40", "X41.64", "X65."), row.names = c(NA, -8L), class = c("data.table", 
"data.frame"), .internal.selfref = <pointer: 0x0000000000200788>)

编辑: 根据下面@Sumedh评论中的建议，性别列不会删除，所有selected_cols都必须是double类型。这是因为来自prop.table的比例是double类型。否则，在对selected_cols执行按引用分配:=时，会出现RHS = LHS数据类型强制转换错误。

setDT(df)[, (selected_cols) := prop.table(.SD), by = location, .SDcols = selected_cols]