如何计算 R 中分类变量组合的行数？

当我们有两个分类变量时，这两个分类变量中的每一个变量对于另一个变量可能都有不同的行数。这有助于我们了解这两个分类变量的组合值。我们可以使用 dplyr 软件包的 count 函数来查找此类行。

示例

考虑基本 R 中的 CO2 数据 −

> head(CO2,20)
> head(CO2,20)
      Plant    Type    Treatment    conc     uptake
1     Qn1     Quebec   nonchilled     95      16.0
2     Qn1     Quebec   nonchilled    175      30.4
3     Qn1     Quebec   nonchilled    250      34.8
4     Qn1     Quebec   nonchilled    350      37.2
5     Qn1     Quebec   nonchilled    500      35.3
6     Qn1     Quebec   nonchilled    675      39.2
7     Qn1     Quebec   nonchilled   1000      39.7
8     Qn2     Quebec   nonchilled     95      13.6
9     Qn2     Quebec   nonchilled    175      27.3
10    Qn2     Quebec   nonchilled    250      37.1
11    Qn2     Quebec   nonchilled    350      41.8
12    Qn2     Quebec   nonchilled    500      40.6
13    Qn2     Quebec   nonchilled    675      41.4
14    Qn2     Quebec   nonchilled   1000      44.3
15    Qn3     Quebec   nonchilled     95      16.2
16    Qn3     Quebec   nonchilled    175      32.4
17    Qn3     Quebec   nonchilled    250      40.3
18    Qn3     Quebec   nonchilled    350      42.1
19    Qn3     Quebec   nonchilled    500      42.9
20    Qn3     Quebec   nonchilled    675      43.9
> tail(CO2,20)  
      Plant    Type        Treatment    conc    uptake
65    Mc1    Mississippi   chilled      175     14.9
66    Mc1    Mississippi   chilled      250     18.1
67    Mc1    Mississippi   chilled      350     18.9
68    Mc1    Mississippi   chilled      500     19.5
69    Mc1    Mississippi   chilled      675     22.2
70    Mc1    Mississippi   chilled     1000     21.9
71    Mc2    Mississippi   chilled       95      7.7
72    Mc2    Mississippi   chilled      175     11.4
73    Mc2    Mississippi   chilled      250     12.3
74    Mc2    Mississippi   chilled      350     13.0
75    Mc2    Mississippi   chilled      500     12.5
76    Mc2    Mississippi   chilled      675     13.7
77    Mc2    Mississippi   chilled    1000      14.4
78    Mc3    Mississippi   chilled      95      10.6
79    Mc3    Mississippi   chilled     175      18.0
80    Mc3    Mississippi   chilled     250      17.9
81    Mc3    Mississippi   chilled     350      17.9
82    Mc3    Mississippi   chilled     500      17.9
83    Mc3    Mississippi   chilled     675      18.9
84    Mc3   Mississippi    chilled    1000      19.9
> library(dplyr)

查找 Type 变量中每个 Treatment 的行数 −

> count(CO2, Type, Treatment)
# A tibble: 4 x 3
Type Treatment n
<fct> <fct> <int>
1 Quebec nonchilled 21
2 Quebec chilled 21
3 Mississippi nonchilled 21
4 Mississippi chilled 21

查找 Type 变量中每个 Plant 的行数 −

> count(CO2, Type, Plant)
# A tibble: 12 x 3
Type Plant n
  <fct> <ord> <int>
1 Quebec Qn1 7
2 Quebec Qn2 7
3 Quebec Qn3 7
4 Quebec Qc1 7
5 Quebec Qc3 7
6 Quebec Qc2 7
7 Mississippi Mn3 7
8 Mississippi Mn2 7
9 Mississippi Mn1 7
10 Mississippi Mc2 7
11 Mississippi Mc3 7
12 Mississippi Mc1 7

查找 Plant 变量中每个 Treatment 的行数 −

> count(CO2, Plant, Treatment)
# A tibble: 12 x 3
Plant Treatment n
<ord> <fct> <int>
1 Qn1 nonchilled 7
2 Qn2 nonchilled 7
3 Qn3 nonchilled 7
4 Qc1 chilled 7
5 Qc3 chilled 7
6 Qc2 chilled 7
7 Mn3 nonchilled 7
8 Mn2 nonchilled 7
9 Mn1 nonchilled 7
10 Mc2 chilled 7
11 Mc3 chilled 7
12 Mc1 chilled 7

Nizamuddin Siddiqui

更新于: 11-8-2020

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