daDoctoR/R/rep_lm.R

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2018-10-02 21:07:43 +02:00
#' A repeated linear regression function
#'
#' For bivariate analyses.
#' @param y Effect meassure.
#' @param v1 Main variable in model
#' @keywords linear regression
#' @export
#' @examples
#' rep_lm()
rep_lm<-function(y,v1,string,ci=FALSE,data,v2=NULL,v3=NULL){
## x is data.frame of predictors, y is vector of an aoutcome as a factor
## output is returned as coefficient, or if ci=TRUE as coefficient with 95 % CI.
## The confint() function is rather slow, causing the whole function to hang when including many predictors and calculating the ORs with CI.
require(broom)
d<-data
x<-select(d,one_of(c(string)))
m1<-length(coef(lm(y~v1)))
if (is.factor(y)){stop("Some kind of error message would be nice, but y should not be a factor!")}
if (ci==TRUE){
df<-data.frame(matrix(ncol = 4))
names(df)<-c("pred","co_ci","pv","t")
for(i in 1:ncol(x)){
m<-lm(y~v1+x[,i])
l<-suppressMessages(round(confint(m)[-c(1:m1),1],2))
u<-suppressMessages(round(confint(m)[-c(1:m1),2],2))
co<-round(coef(m)[-c(1:m1)],2)
co_ci<-paste0(co," (",l," to ",u,")")
pv<-round(tidy(m)$p.value[-c(1:m1)],3)
pv<-ifelse(pv<0.001,"<0.001",pv)
t <- ifelse(pv<=0.1|pv=="<0.001","include","drop")
pv <- ifelse(pv<=0.05|pv=="<0.001",paste0("*",pv),
ifelse(pv>0.05&pv<=0.1,paste0(".",pv),pv))
v<-x[,i]
if (is.factor(v)){
pred<-paste(names(x)[i],levels(v)[-1],sep = "_")
}
else {pred<-names(x)[i]}
df<-rbind(df,cbind(pred,co_ci,pv,t))
}}
if (ci==FALSE){
df<-data.frame(matrix(ncol = 4))
names(df)<-c("pred","b","pv","t")
for(i in 1:ncol(x)){
m<-lm(y~v1+x[,i])
b<-round(coef(m)[-c(1:m1)],3)
pv<-round(tidy(m)$p.value[-c(1:m1)],3)
pv<-ifelse(pv<0.001,"<0.001",pv)
t <- ifelse(pv<=0.1|pv=="<0.001","include","drop")
pv <- ifelse(pv<=0.05|pv=="<0.001",paste0("*",pv),
ifelse(pv>0.05&pv<=0.1,paste0(".",pv),pv))
v<-x[,i]
if (is.factor(v)){
pred<-paste(names(x)[i],levels(v)[-1],sep = "_")
}
else {pred<-names(x)[i]}
df<-rbind(df,cbind(pred,b,pv,t))
}}
return(df)
}