Difference between revisions of "Goherr: Fish consumption study"

library(OpasnetUtils)
library(reshape2)
library(ggplot2)

############## Generic functions and objects are defined first.

### webropol.convert converts a csv file from Webropol into a useful data.frame.

webropol.convert <- function(
  data, # Data.frame created from a Webropol csv file. The first row should contain headings.
  rowfact, # Row number where the factor levels start (in practice, last row + 3)
  textmark = "Other open" # The text that is shown in the heading if there is an open sub-question.
) {
  out <- dropall(data[2:(rowfact - 3) , ])
  subquestion <- t(data[1 , ])
  subquestion <- gsub("\xa0", " ", subquestion)
  subquestion <- gsub("\xb4", " ", subquestion)
  subquestion <- gsub("\n", " ", subquestion)
  #  subquestion <- gsub("\\(", " ", subquestion)
  #  subquestion <- gsub("\\)", " ", subquestion)
  textfield <- regexpr(textmark, subquestion) != -1
  subquestion <- strsplit(subquestion, ":") # Divide the heading into a main question and a subquestion.
  subqtest <- 0 # The previous question name.
  for(i in 1:ncol(out)) {
    print(i)
    if(subquestion[[i]][1] != subqtest) { # If part of previous question, use previous fact.
      fact <- as.character(data[rowfact:nrow(data) , i]) # Create factor levels from the end of Webropol file.
      fact <- fact[fact != ""] # Remove empty rows
      fact <- gsub("\xa0", " ", fact)
      fact <- gsub("\xb4", " ", fact)
      fact <- gsub("\n", " ", fact)
      fact <- strsplit(fact, " = ") # Separate value (level) and interpretation (label)
    }
    if(length(fact) != 0 & !textfield[i]) { # Do this only if the column is not a text type column.
      out[[i]] <- factor(
        out[[i]], 
        levels = unlist(lapply(fact, function(x) x[1])), 
        labels = unlist(lapply(fact, function(x) x[2])), 
        ordered = TRUE
      )
    }
    subqtest <- subquestion[[i]][1]
  }
  return(out)
}

# merge.questions takes a multiple checkbox question and merges that into a single factor.
# First levels in levs have priority over others, if several levels apply to a row.

merge.questions <- function(
  dat, # data.frame with questionnaire data
  cols, # list of vectors of column names or numbers to be merged into one level in the factor
  levs, # vector (with the same length as cols) of levels of factors into which questions are merged.
  name # text string for the name of the new factor column in the data.
) {
  for(i in length(cols):1) {
    temp <- FALSE
    for(j in rev(cols[[i]])) {
      temp <- temp | !is.na(dat[[j]])
    }
    dat[[name]][temp] <- levs[i]
  }
  dat[[name]] <- factor(dat[[name]], levels = levs, ordered = TRUE)
  return(dat)
}

############# Data preprocessing

# Get the data either from Opasnet or your own hard drive.

#Survey original file: N:/Ymal/Projects/Goherr/WP5/Goherr_fish_consumption.csv

survey <- opasnet.csv("5/57/Goherr_fish_consumption.csv", sep = ";", fill = TRUE, quote = "\"")
surcol <- t(survey[1,])

survey <- webropol.convert(survey, 2121, textmark = ":Other open") # Data file is converted to data.frame using levels at row 1269.

# Take the relevant columnames from the table on the page.
#colnames(survey1) <- opbase.data("Heande3951",subset="Survey 1 questions")[1:ncol(survey1), "Name"]

ggplot(survey, aes(x = as.numeric(V4), fill = V3)) + geom_histogram(position = "dodge") +
  theme_gray(base_size = 18) + theme(axis.text.x=element_text(angle=90,hjust=1,vjust=0.4)) + facet_wrap(~ V1)