Separate conduction of conjugacy tables in R - r

Question

In my dataset there are 7 binary (categorical) variables (x1-x7.)
Another vars are scale and we won't use it.
mydat(part of)
structure(list(city = structure(c(2L, 2L, 2L, 2L, 2L, 1L, 1L,
1L, 1L, 1L), .Label = c("New-York", "Washington"), class = "factor"),
x1 = c(0L, 0L, 1L, 1L, 0L, 0L, 0L, 1L, 1L, 0L), x2 = c(0L,
0L, 1L, 1L, 0L, 0L, 0L, 1L, 1L, 0L), x3 = c(0L, 0L, 1L, 1L,
0L, 0L, 0L, 1L, 1L, 0L), x4 = c(0L, 0L, 1L, 1L, 0L, 0L, 0L,
1L, 1L, 0L), x5 = c(0L, 0L, 1L, 1L, 0L, 0L, 0L, 1L, 1L, 0L
), x6 = c(0L, 0L, 1L, 1L, 0L, 0L, 0L, 1L, 1L, 0L), x7 = c(0L,
0L, 1L, 1L, 0L, 0L, 0L, 1L, 1L, 0L), var1 = c(10L, 71L, 49L,
70L, 79L, 46L, 87L, 57L, 81L, 68L), var2 = c(34L, 17L, 28L,
63L, 95L, 99L, 40L, 63L, 24L, 90L), var3 = c(21L, 89L, 81L,
26L, 59L, 87L, 84L, 24L, 27L, 83L), var4 = c(86L, 70L, 45L,
40L, 95L, 94L, 39L, 97L, 89L, 30L)), .Names = c("city", "x1",
"x2", "x3", "x4", "x5", "x6", "x7", "var1", "var2", "var3", "var4"
), class = "data.frame", row.names = c(NA, -10L))
I created the function which perform cross-tabs between all binary variables.
Perhaps maybe it will be useful for anybody.
It works.
mydat=read.csv(mydat)
library("gmodels")
mult_crosstab <- function (data = cross) {
for (j in 1:(ncol(data)-1)) {
for (i in (j+1):(ncol(data))) {
x <- names(data)[j]
y <- names(data)[i]
call <- call("CrossTable", as.name(x), as.name(y), chisq = TRUE)
eval(call, data)
}
}
}
mult_crosstab()
But in dataset - mydat there is variable city (Washington and New-York).
How to use my fuction to calculcate the cross-tabs for two cities separately?

Answer 1

Split your data by city, then iterate over each split and run your function
lapply(split(cross, cross$city), mult_crosstab)
It seems that CrossTable is a nasty little function that prints to the console instead of returning an object. You can capture your output as text with capture.output(code_above) if that is what you desire.