我有一个与expss表有关的(新)问题。我写了一个非常简单的UDF(依赖于少数的expss函数),如下所示。
library(expss)
z_indices <- function(x, m_global, std_global, weight=NULL){
if(is.null(weight)) weight = rep(1, length(x))
z <- (w_mean(x, weight)-m_global)/std_global
indices <- 100+(z*100)
return(indices)
}
可复制的例子,基于 infert
数据集(加上一个任意权重的向量)。
data(infert)
infert$w <- as.vector(x=rep(2, times=nrow(infert)), mode='numeric')
infert %>%
tab_cells(age, parity) %>%
tab_cols(total(), education, case %nest% list(total(), education)) %>%
tab_weight(w) %>%
tab_stat_valid_n(label="N") %>%
tab_stat_mean(label="Mean") %>%
tab_stat_fun(label="Z", function(x, m_global, std_global, weight=NULL){
z_indices(x, m_global=w_mean(infert$age, infert$w),std_global=w_sd(infert$age, infert$w))
}) %>%
tab_pivot(stat_position="inside_columns")
表被计算出来,第一行的输出(几乎)和预期一样。z_indices
明指 infert$age
,其中 infert$parity
我的问题是:是否有办法动态地将 tab_cells
作为函数参数在 tab_stat_fun
来匹配正在处理的变量?我想这是在函数声明中发生的,但不知道如何处理......
谢谢
2020年4月28日编辑。来自@Gregory Demin的回答 在infert数据集的范围内效果很好,不过为了更好地扩展到更大的数据框,我写了下面的循环。
var_df <- data.frame("age"=infert$age, "parity"=infert$parity)
tabZ=infert
for(each in names(var_df)){
tabZ = tabZ %>%
tab_cells(var_df[each]) %>%
tab_cols(total(), education) %>%
tab_weight(w) %>%
tab_stat_valid_n(label="N") %>%
tab_stat_mean(label="Mean") %>%
tab_stat_fun(label="Z", function(x, m_global, std_global, weight=NULL){
z_indices(x, m_global=w_mean(var_df[each], infert$w),std_global=w_sd(var_df[each], infert$w))
})
}
tabZ = tabZ %>% tab_pivot()
希望这对未来其他expss用户有所启发!
对于这种情况,没有通用的解决方案。功能在 tab_stat_fun
然而,在你的情况下,我们可以在汇总之前计算z-index。虽然不是那么灵活的解决方案,但它是可行的。
# function for weighted z-score
w_z_index = function(x, weight = NULL){
if(is.null(weight)) weight = rep(1, length(x))
z <- (x - w_mean(x, weight))/w_sd(x, weight)
indices <- 100+(z*100)
return(indices)
}
data(infert)
infert$w <- rep(2, times=nrow(infert))
infert %>%
tab_cells(age, parity) %>%
tab_cols(total(), education, case %nest% list(total(), education)) %>%
tab_weight(w) %>%
tab_stat_valid_n(label="N") %>%
tab_stat_mean(label="Mean") %>%
# here we get z-index instead of original variables
tab_cells(age = w_z_index(age, w), parity = w_z_index(parity, w)) %>%
tab_stat_mean(label="Z") %>%
tab_pivot(stat_position="inside_columns")
UPDATE.一个更可扩展的方法。
w_z_index = function(x, weight = NULL){
if(is.null(weight)) weight = rep(1, length(x))
z <- (x - w_mean(x, weight))/w_sd(x, weight)
indices <- 100+(z*100)
return(indices)
}
w_z_index_df = function(df, weight = NULL){
df[] = lapply(df, w_z_index, weight = weight)
df
}
data(infert)
infert$w <- rep(2, times=nrow(infert))
infert %>%
tab_cells(age, parity) %>%
tab_cols(total(), education, case %nest% list(total(), education)) %>%
tab_weight(w) %>%
tab_stat_valid_n(label="N") %>%
tab_stat_mean(label="Mean") %>%
# here we get z-index instead of original variables
# we process a lot of variables at once
tab_cells(w_z_index_df(data.frame(age, parity))) %>%
tab_stat_mean(label="Z") %>%
tab_pivot(stat_position="inside_columns")