如何获得列联表? [英] How do I get a contingency table?

问题描述

I am trying to create a contingency table from a particular type of data. This would be doable with loops etc... but because my final table would contain more than 10E5 cells, I am looking for a pre-existing function.

My initial data are as follow:

PLANT                  ANIMAL                          INTERACTIONS
---------------------- ------------------------------- ------------
Tragopogon_pratensis   Propylea_quatuordecimpunctata         1
Anthriscus_sylvestris  Rhagonycha_nigriventris               3
Anthriscus_sylvestris  Sarcophaga_carnaria                   2
Heracleum_sphondylium  Sarcophaga_carnaria                   1
Anthriscus_sylvestris  Sarcophaga_variegata                  4
Anthriscus_sylvestris  Sphaerophoria_interrupta_Gruppe       3
Cerastium_holosteoides Sphaerophoria_interrupta_Gruppe       1

I would like to create a table like this:

                       Propylea_quatuordecimpunctata Rhagonycha_nigriventris Sarcophaga_carnaria Sarcophaga_variegata Sphaerophoria_interrupta_Gruppe
---------------------- ----------------------------- ----------------------- ------------------- -------------------- -------------------------------
Tragopogon_pratensis   1                             0                       0                   0                    0
Anthriscus_sylvestris  0                             3                       2                   4                    3
Heracleum_sphondylium  0                             0                       1                   0                    0
Cerastium_holosteoides 0                             0                       0                   0                    1

That is, all plant species in row, all animal species in columns, and sometimes there are no interactions (while my initial data only list interactions that occur).

解决方案

In base R, use table or xtabs:

with(warpbreaks, table(wool, tension))

    tension
wool L M H
   A 9 9 9
   B 9 9 9

xtabs(~wool+tension, data=warpbreaks)

    tension
wool L M H
   A 9 9 9
   B 9 9 9

The gmodels packages has a function CrossTable that gives output similar to what users of SPSS or SAS expects:

library(gmodels)
with(warpbreaks, CrossTable(wool, tension))


   Cell Contents
|-------------------------|
|                       N |
| Chi-square contribution |
|           N / Row Total |
|           N / Col Total |
|         N / Table Total |
|-------------------------|


Total Observations in Table:  54 


             | tension 
        wool |         L |         M |         H | Row Total | 
-------------|-----------|-----------|-----------|-----------|
           A |         9 |         9 |         9 |        27 | 
             |     0.000 |     0.000 |     0.000 |           | 
             |     0.333 |     0.333 |     0.333 |     0.500 | 
             |     0.500 |     0.500 |     0.500 |           | 
             |     0.167 |     0.167 |     0.167 |           | 
-------------|-----------|-----------|-----------|-----------|
           B |         9 |         9 |         9 |        27 | 
             |     0.000 |     0.000 |     0.000 |           | 
             |     0.333 |     0.333 |     0.333 |     0.500 | 
             |     0.500 |     0.500 |     0.500 |           | 
             |     0.167 |     0.167 |     0.167 |           | 
-------------|-----------|-----------|-----------|-----------|
Column Total |        18 |        18 |        18 |        54 | 
             |     0.333 |     0.333 |     0.333 |           | 
-------------|-----------|-----------|-----------|-----------|

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