Welcome to the linelist package!

This package is dedicated to simplifying the cleaning and standardisation of linelist data. Considering a case linelist data.frame, it aims to:

• standardise the variables names, replacing all non-ascii characters with their closest latin equivalent, removing blank spaces and other separators, enforcing lower case capitalisation, and using a single separator between words

• standardise the labels used in all variables of type character and factor, as above

• set POSIXct and POSIXlt to Date objects

• extract dates from a messy variable, automatically detecting formats, allowing inconsistent formats, and dates flanked by other text

• support data dictionary: linelist objects can store meta-data indicating which columns correspond to standard epidemiological variables, usually found in linelists such as a unique identifier, gender, or dates of onset

Installing the package

To install the current stable, CRAN version of the package, type:

install.packages("linelist")

To benefit from the latest features and bug fixes, install the development, github version of the package using:

devtools::install_github("reconhub/linelist")

Note that this requires the package devtools installed.

What does it do?

Data cleaning

Procedures to clean data, first and foremost aimed at data.frame formats, include:

• clean_data(): the main function, taking a data.frame as input, and doing all the variable names, internal labels, and date processing described above

• clean_variable_names(): like clean_data, but only the variable names

• clean_variable_labels(): like clean_data, but only the variable labels

• clean_variable_spelling(): provided with a dictionary, will correct the spelling of values in a variable and can globally correct commonly mis-spelled words.

• clean_dates(): like clean_data, but only the dates

• guess_dates(): find dates in various, unspecified formats in a messy character vector

• as_linelist(): create a new linelist object from a data.frame

Dictionary

linelist also handles a dictionary of pre-defined, standard epidemiological variables, referred to as epivars throughout the package. Meta-information can be attached to linelist objects to define which columns of the dataset correspond to specific epivars.

The main functions to handle the epivars of a linelist object include:

• list_epivars(): lists the epivars of a dataset, with options to have more or less information

• get_epivars(): extract columns of a dataset corresponding to epivars

• set_epivars(): set the epivars of a dataset

• as_linelist(): creates a new linelist object, and can define epivars as extra arguments

In addition, several functions allow to interact with the dictionary of recognised epivars, including:

• default_dictionary(): shows the default dictionary of epivars

• get_dictionary(): shows the current epivars dictionary

• set_dictionary(): set the current epivars dictionary; if arguments are empty, reset to the defaults

• reset_dictionary(): reset the current epivars dictionary to defaults

Worked example

Let us consider some messy data.frame as a toy example:

## make toy data
onsets <- as.Date("2018-01-01") + sample(1:10, 20, replace = TRUE)
discharge <- format(as.Date(onsets) + 10, "%d/%m/%Y")
genders <- c("male", "female", "FEMALE", "Male", "Female", "MALE")
gender <- sample(genders, 20, replace = TRUE)
case_types <- c("confirmed", "probable", "suspected", "not a case",
                "Confirmed", "PROBABLE", "suspected  ", "Not.a.Case")
messy_dates <- sample(
                 c("01-12-2001", "male", "female", "2018-10-18", "2018_10_17",
                   "2018 10 19", "// 24//12//1989", NA, "that's 24/12/1989!"),
                 20, replace = TRUE)
case <- factor(sample(case_types, 20, replace = TRUE))
toy_data <- data.frame("Date of Onset." = onsets,
                       "DisCharge.." = discharge,
                       "SeX_ " = gender,
                       "Épi.Case_définition" = case,
                       "messy/dates" = messy_dates)
## show data
toy_data
#>    Date.of.Onset. DisCharge..  SeX_. Épi.Case_définition
#> 1      2018-01-06  16/01/2018   Male           suspected
#> 2      2018-01-05  15/01/2018 female            probable
#> 3      2018-01-02  12/01/2018 Female            probable
#> 4      2018-01-03  13/01/2018 Female          not a case
#> 5      2018-01-10  20/01/2018 FEMALE            probable
#> 6      2018-01-08  18/01/2018 FEMALE            probable
#> 7      2018-01-03  13/01/2018   Male           confirmed
#> 8      2018-01-05  15/01/2018   Male          Not.a.Case
#> 9      2018-01-09  19/01/2018 FEMALE           suspected
#> 10     2018-01-08  18/01/2018   MALE          not a case
#> 11     2018-01-07  17/01/2018 Female            probable
#> 12     2018-01-06  16/01/2018   MALE            PROBABLE
#> 13     2018-01-11  21/01/2018 female            PROBABLE
#> 14     2018-01-06  16/01/2018 female           Confirmed
#> 15     2018-01-08  18/01/2018   Male          Not.a.Case
#> 16     2018-01-02  12/01/2018 FEMALE         suspected  
#> 17     2018-01-07  17/01/2018 Female          not a case
#> 18     2018-01-10  20/01/2018 Female            probable
#> 19     2018-01-05  15/01/2018   Male           Confirmed
#> 20     2018-01-09  19/01/2018   Male          Not.a.Case
#>           messy.dates
#> 1  that's 24/12/1989!
#> 2          01-12-2001
#> 3                male
#> 4                male
#> 5          2018 10 19
#> 6  that's 24/12/1989!
#> 7          2018_10_17
#> 8          2018_10_17
#> 9              female
#> 10               <NA>
#> 11               <NA>
#> 12         01-12-2001
#> 13 that's 24/12/1989!
#> 14    // 24//12//1989
#> 15         2018-10-18
#> 16         2018-10-18
#> 17         2018_10_17
#> 18 that's 24/12/1989!
#> 19         2018_10_17
#> 20         01-12-2001

We start by cleaning these data:

## load library
library(linelist)

## clean data with defaults
x <- clean_data(toy_data)
x
#>    date_of_onset  discharge    sex epi_case_definition messy_dates
#> 1     2018-01-06 2018-01-16   male           suspected  1989-12-24
#> 2     2018-01-05 2018-01-15 female            probable  2001-12-01
#> 3     2018-01-02 2018-01-12 female            probable        <NA>
#> 4     2018-01-03 2018-01-13 female          not_a_case        <NA>
#> 5     2018-01-10 2018-01-20 female            probable  2018-10-19
#> 6     2018-01-08 2018-01-18 female            probable  1989-12-24
#> 7     2018-01-03 2018-01-13   male           confirmed  2018-10-17
#> 8     2018-01-05 2018-01-15   male          not_a_case  2018-10-17
#> 9     2018-01-09 2018-01-19 female           suspected        <NA>
#> 10    2018-01-08 2018-01-18   male          not_a_case        <NA>
#> 11    2018-01-07 2018-01-17 female            probable        <NA>
#> 12    2018-01-06 2018-01-16   male            probable  2001-12-01
#> 13    2018-01-11 2018-01-21 female            probable  1989-12-24
#> 14    2018-01-06 2018-01-16 female           confirmed  1989-12-24
#> 15    2018-01-08 2018-01-18   male          not_a_case  2018-10-18
#> 16    2018-01-02 2018-01-12 female           suspected  2018-10-18
#> 17    2018-01-07 2018-01-17 female          not_a_case  2018-10-17
#> 18    2018-01-10 2018-01-20 female            probable  1989-12-24
#> 19    2018-01-05 2018-01-15   male           confirmed  2018-10-17
#> 20    2018-01-09 2018-01-19   male          not_a_case  2001-12-01

We can now define some epivars for x, i.e. identify which columns correspond to typical epidemiological variables:

## see what the dictionary is
get_dictionary()
#>             epivar              hxl
#> 1               id       #respondee
#> 2       date_onset     #date +start
#> 3      date_report  #date +reported
#> 4     date_outcome       #date +end
#> 5  case_definition #indicator +name
#> 6          outcome #indicator +type
#> 7           gender #indicator +type
#> 8              age  #indicator +num
#> 9        age_group #indicator +type
#> 10         geo_lon        #geo +lon
#> 11         geo_lat        #geo +lat
#>                                            description
#> 1                         unique individual identifier
#> 2                       date at which symptoms started
#> 3                      date at which case was reported
#> 4              date of the outcome (recovery or death)
#> 5  case type: suspected, probable, confirmed, negative
#> 6                                    recovery or death
#> 7                             gender of the individual
#> 8                       age of the individual in years
#> 9                 age group of the individual in years
#> 10                    geographic coordinate: longitude
#> 11                     geographic coordinate: latitude

## see current names of variables
names(x)
#> [1] "date_of_onset"       "discharge"           "sex"                
#> [4] "epi_case_definition" "messy_dates"

## some variables are known epivars; let's create a linelist object and register
## this information at the same time
x <- as_linelist(x, date_onset = "date_of_onset", gender = "sex")
x
#> <linelist object>
#> 
#>    date_of_onset  discharge    sex epi_case_definition messy_dates
#> 1     2018-01-06 2018-01-16   male           suspected  1989-12-24
#> 2     2018-01-05 2018-01-15 female            probable  2001-12-01
#> 3     2018-01-02 2018-01-12 female            probable        <NA>
#> 4     2018-01-03 2018-01-13 female          not_a_case        <NA>
#> 5     2018-01-10 2018-01-20 female            probable  2018-10-19
#> 6     2018-01-08 2018-01-18 female            probable  1989-12-24
#> 7     2018-01-03 2018-01-13   male           confirmed  2018-10-17
#> 8     2018-01-05 2018-01-15   male          not_a_case  2018-10-17
#> 9     2018-01-09 2018-01-19 female           suspected        <NA>
#> 10    2018-01-08 2018-01-18   male          not_a_case        <NA>
#> 11    2018-01-07 2018-01-17 female            probable        <NA>
#> 12    2018-01-06 2018-01-16   male            probable  2001-12-01
#> 13    2018-01-11 2018-01-21 female            probable  1989-12-24
#> 14    2018-01-06 2018-01-16 female           confirmed  1989-12-24
#> 15    2018-01-08 2018-01-18   male          not_a_case  2018-10-18
#> 16    2018-01-02 2018-01-12 female           suspected  2018-10-18
#> 17    2018-01-07 2018-01-17 female          not_a_case  2018-10-17
#> 18    2018-01-10 2018-01-20 female            probable  1989-12-24
#> 19    2018-01-05 2018-01-15   male           confirmed  2018-10-17
#> 20    2018-01-09 2018-01-19   male          not_a_case  2001-12-01

Note that the equivalent can be done using piping:

library(magrittr)
x <- toy_data %>%
  clean_data %>%
  as_linelist(date_onset = "date_of_onset", gender = "sex")
x
#> <linelist object>
#> 
#>    date_of_onset  discharge    sex epi_case_definition messy_dates
#> 1     2018-01-06 2018-01-16   male           suspected  1989-12-24
#> 2     2018-01-05 2018-01-15 female            probable  2001-12-01
#> 3     2018-01-02 2018-01-12 female            probable        <NA>
#> 4     2018-01-03 2018-01-13 female          not_a_case        <NA>
#> 5     2018-01-10 2018-01-20 female            probable  2018-10-19
#> 6     2018-01-08 2018-01-18 female            probable  1989-12-24
#> 7     2018-01-03 2018-01-13   male           confirmed  2018-10-17
#> 8     2018-01-05 2018-01-15   male          not_a_case  2018-10-17
#> 9     2018-01-09 2018-01-19 female           suspected        <NA>
#> 10    2018-01-08 2018-01-18   male          not_a_case        <NA>
#> 11    2018-01-07 2018-01-17 female            probable        <NA>
#> 12    2018-01-06 2018-01-16   male            probable  2001-12-01
#> 13    2018-01-11 2018-01-21 female            probable  1989-12-24
#> 14    2018-01-06 2018-01-16 female           confirmed  1989-12-24
#> 15    2018-01-08 2018-01-18   male          not_a_case  2018-10-18
#> 16    2018-01-02 2018-01-12 female           suspected  2018-10-18
#> 17    2018-01-07 2018-01-17 female          not_a_case  2018-10-17
#> 18    2018-01-10 2018-01-20 female            probable  1989-12-24
#> 19    2018-01-05 2018-01-15   male           confirmed  2018-10-17
#> 20    2018-01-09 2018-01-19   male          not_a_case  2001-12-01

We now handle a clean dataset, with standardised labels and variable names, and dates of onset and gender are now formally identifier:

## check available epivars
list_epivars(x, simple = TRUE) # simple
#> [1] "date_onset" "gender"
list_epivars(x) # more info
#>       epivar        column              hxl                    description
#> 1 date_onset date_of_onset     #date +start date at which symptoms started
#> 2     gender           sex #indicator +type       gender of the individual


get_epivars(x, "gender", "date_onset")
#>       sex date_of_onset
#> 1    male    2018-01-06
#> 2  female    2018-01-05
#> 3  female    2018-01-02
#> 4  female    2018-01-03
#> 5  female    2018-01-10
#> 6  female    2018-01-08
#> 7    male    2018-01-03
#> 8    male    2018-01-05
#> 9  female    2018-01-09
#> 10   male    2018-01-08
#> 11 female    2018-01-07
#> 12   male    2018-01-06
#> 13 female    2018-01-11
#> 14 female    2018-01-06
#> 15   male    2018-01-08
#> 16 female    2018-01-02
#> 17 female    2018-01-07
#> 18 female    2018-01-10
#> 19   male    2018-01-05
#> 20   male    2018-01-09

Getting help online

Bug reports and feature requests should be posted on github using the issue system. All other questions should be posted on the RECON forum:
http://www.repidemicsconsortium.org/forum/

Contributions are welcome via pull requests.

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.

Roadmap

The linelist package should have the following features in the future:

• A data dictionary that allows you to map standard variable names to columns
• Integration with #hxl standard
• Validation of categorical values