Importing and Exporting Data

library(mariposa)
library(dplyr)
data(survey_data)

Overview

Survey data lives in many formats — SPSS (.sav), Stata (.dta), SAS (.sas7bdat), and Excel (.xlsx). mariposa reads all of them and preserves the metadata that makes survey data special: variable labels, value labels, and missing value definitions.

Function Format Notes
read_spss() SPSS .sav Tagged NA support for user-defined missing values
read_por() SPSS .por Portable SPSS format
read_stata() Stata .dta Extended missing values
read_sas() SAS .sas7bdat Catalog file support for labels
read_xpt() SAS .xpt SAS transport format
read_xlsx() Excel .xlsx Label reconstruction from metadata sheets

For export, mariposa writes data back to statistical formats with full preservation of labels and missing values:

Function Format Notes
write_spss() SPSS .sav Tagged NA roundtripping
write_stata() Stata .dta Label preservation
write_xpt() SAS .xpt SAS transport format
write_xlsx() Excel .xlsx Multiple export modes (data, codebook, frequencies)

Reading SPSS Files

Basic Import

SPSS is the most common format in survey research. read_spss() reads .sav files and preserves all metadata:

# Read an SPSS file
data <- read_spss("survey_2024.sav")

The result is a tibble with haven_labelled columns. Each column carries its variable label, value labels, and missing value definitions as attributes.

Tagged Missing Values

SPSS allows researchers to define multiple types of missing values (e.g., -9 = “refused”, -8 = “don’t know”, -7 = “not applicable”). By default, read_spss() preserves these as tagged NAs — special NA values that remember which missing code they came from:

# Tagged NAs are on by default
data <- read_spss("survey.sav", tag_na = TRUE)

# Turn off if you just want regular NAs
data <- read_spss("survey.sav", tag_na = FALSE)

Working with Tagged NAs

Once imported, you can inspect the tagged NAs:

# See a breakdown of missing types
na_frequencies(data, q1, q2, q3)

# Convert tagged NAs back to their original codes
data_with_codes <- untag_na(data, q1, q2)

# Remove tags but keep NAs
data_clean <- strip_tags(data)

na_frequencies() is particularly useful for understanding response patterns — it shows you how many respondents refused, said “don’t know”, or skipped each question.

Reading Other Formats

Stata

data <- read_stata("survey.dta")

Stata files carry variable labels and value labels, similar to SPSS. Extended missing values (.a through .z) are preserved.

SAS

# SAS data file
data <- read_sas("survey.sas7bdat")

# With a separate catalog file for labels
data <- read_sas("survey.sas7bdat", catalog_file = "formats.sas7bcat")

# SAS transport format
data <- read_xpt("survey.xpt")

SPSS Portable

data <- read_por("survey.por")

Excel

# Basic Excel import
data <- read_xlsx("survey.xlsx")

# Excel file with label metadata (exported by write_xlsx)
data <- read_xlsx("survey.xlsx", label_sheet = "labels")

read_xlsx() can reconstruct variable and value labels from a metadata sheet, enabling a full roundtrip through Excel format.

Inspecting Imported Data

After importing, use codebook() to get an interactive overview of your data:

codebook(survey_data)

The codebook displays in the RStudio Viewer and shows:

For a quick look at variable names and labels without leaving the console, use find_var():

# Find variables related to "trust"
find_var(survey_data, "trust")
#>   col             name                                    label
#> 1  11 trust_government Trust in government (1=none, 5=complete)
#> 2  12      trust_media      Trust in media (1=none, 5=complete)
#> 3  13    trust_science    Trust in science (1=none, 5=complete)

# Search by variable label
find_var(survey_data, "satisfaction", search = "label")
#>   col              name                                           label
#> 1  10 life_satisfaction Life satisfaction (1=dissatisfied, 5=satisfied)

Exporting Data

Writing SPSS Files

write_spss() creates .sav files with full preservation of labels and missing values. If your data contains tagged NAs (from read_spss()), they are converted back to SPSS user-defined missing values:

# Basic export
write_spss(survey_data, "output.sav")

# With compression options
write_spss(survey_data, "output.sav", compress = "zsav")  # smaller file

Writing Stata Files

write_stata(survey_data, "output.dta")

Writing SAS Transport Files

write_xpt(survey_data, "output.xpt")

Writing Excel Files

write_xlsx() supports multiple export modes:

# Export data only
write_xlsx(survey_data, "output.xlsx")

# Export a codebook
cb <- codebook(survey_data)
write_xlsx(cb, "codebook.xlsx")

# Export frequency tables
freq <- frequency(survey_data, education, employment)
write_xlsx(freq, "frequencies.xlsx")

Roundtripping: SPSS → R → SPSS

A key strength of mariposa is lossless roundtripping. Data imported from SPSS can be exported back without losing any information:

# 1. Import from SPSS
original <- read_spss("survey.sav")

# 2. Work with the data in R
processed <- original %>%
  filter(age >= 18) %>%
  mutate(age_group = rec(., age, rules = "18:29=1; 30:49=2; 50:99=3"))

# 3. Export back to SPSS
write_spss(processed, "survey_processed.sav")

# Variable labels, value labels, and missing value definitions
# are all preserved in the exported file.

Practical Tips

  1. Always use read_spss() over haven::read_sav() when your SPSS file uses user-defined missing values. The tagged NA system preserves the distinction between “refused” and “don’t know” responses.

  2. Inspect before analyzing. After import, run codebook() or find_var() to understand what variables are available and how they are coded.

  3. Keep tagged NAs during analysis. All mariposa functions handle tagged NAs correctly — they are treated as missing values in computations but retain their type information.

  4. Use strip_tags() when handing data to non-mariposa functions. Some R functions may not handle tagged NAs correctly. Strip the tags first to convert them to regular NAs.

  5. Prefer write_spss() for SPSS users. The roundtripping ensures your colleagues can open the file in SPSS with all metadata intact.

Summary

  1. read_spss(), read_stata(), read_sas(), read_xlsx() import data with full metadata preservation
  2. Tagged NAs preserve SPSS user-defined missing value types
  3. codebook() and find_var() help you understand imported data quickly
  4. write_spss(), write_stata(), write_xpt(), write_xlsx() export with label and missing value roundtripping
  5. The full import-export cycle is lossless for SPSS data

Next Steps