Package 'matchmaker'

Title: Flexible Dictionary-Based Cleaning
Description: Provides flexible dictionary-based cleaning that allows users to specify implicit and explicit missing data, regular expressions for both data and columns, and global matches, while respecting ordering of factors. This package is part of the 'RECON' (<https://www.repidemicsconsortium.org/>) toolkit for outbreak analysis.
Authors: Zhian N. Kamvar [aut, cre] , Thibaut Jombart [ctb], Patrick Barks [ctb]
Maintainer: Zhian N. Kamvar <[email protected]>
License: GPL-3
Version: 0.1.1
Built: 2024-10-08 03:16:40 UTC
Source: https://github.com/reconhub/matchmaker

Help Index


Check and clean spelling or codes of multiple variables in a data frame

Description

This function allows you to clean your data according to pre-defined rules encapsulated in either a data frame or list of data frames. It has application for addressing mis-spellings and recoding variables (e.g. from electronic survey data).

Usage

match_df(
  x = data.frame(),
  dictionary = list(),
  from = 1,
  to = 2,
  by = 3,
  order = NULL,
  warn = FALSE
)

Arguments

x

a character or factor vector

dictionary

a data frame or named list of data frames with at least two columns defining the word list to be used. If this is a data frame, a third column must be present to split the dictionary by column in x (see by).

from

a column name or position defining words or keys to be replaced

to

a column name or position defining replacement values

by

character or integer. If dictionary is a data frame, then this column in defines the columns in x corresponding to each section of the dictionary data frame. This defaults to 3, indicating the third column is to be used.

order

a character the column to be used for sorting the values in each data frame. If the incoming variables are factors, this determines how the resulting factors will be sorted.

warn

if TRUE, warnings and errors from match_vec() will be shown as a single warning. Defaults to FALSE, which shows nothing.

Details

By default, this applies the function match_vec() to all columns specified by the column names listed in by, or, if a global dictionary is used, this includes all character and factor columns as well.

by column

Spelling variables within dictionary represent keys that you want to match to column names in x (the data set). These are expected to match exactly with the exception of two reserved keywords that starts with a full stop:

  • .regex [pattern]: any column whose name is matched by ⁠[pattern]⁠. The ⁠[pattern]⁠ should be an unquoted, valid, PERL-flavored regular expression.

  • .global: any column (see Section Global dictionary)

Global dictionary

A global dictionary is a set of definitions applied to all valid columns of x indiscriminantly.

  • .global keyword in by: If you want to apply a set of definitions to all valid columns in addition to specified columns, then you can include a .global group in the by column of your dictionary data frame. This is useful for setting up a dictionary of common spelling errors. NOTE: specific variable definitions will override global defintions. For example: if you have a column for cardinal directions and a definiton for N = North, then the global variable N = no will not override that. See Example.

  • by = NULL: If you want your data frame to be applied to all character/factor columns indiscriminantly, then setting by = NULL will use that dictionary globally.

Value

a data frame with re-defined data based on the dictionary

Author(s)

Zhian N. Kamvar

Patrick Barks

See Also

match_vec(), which this function wraps.

Examples

# Read in dictionary and coded date examples --------------------

dict <- read.csv(matchmaker_example("spelling-dictionary.csv"),
  stringsAsFactors = FALSE)
dat <- read.csv(matchmaker_example("coded-data.csv"),
  stringsAsFactors = FALSE)
dat$date <- as.Date(dat$date)

# Clean spelling based on dictionary -----------------------------

dict # show the dict
head(dat) # show the data

res1 <- match_df(dat,
  dictionary = dict,
  from = "options",
  to = "values",
  by = "grp")
head(res1)

# Show warnings/errors from each column --------------------------
# Internally, the `match_vec()` function can be quite noisy with warnings for
# various reasons. Thus, by default, the `match_df()` function will keep
# these quiet, but you can have them printed to your console if you use the
# warn = TRUE option:

res1 <- match_df(dat,
  dictionary = dict,
  from = "options",
  to = "values",
  by = "grp",
  warn = TRUE)
head(res1)


# You can ensure the order of the factors are correct by specifying
# a column that defines order.

dat[] <- lapply(dat, as.factor)
as.list(head(dat))
res2 <- match_df(dat,
  dictionary = dict,
  from = "options",
  to = "values",
  by = "grp",
  order = "orders")
head(res2)
as.list(head(res2))

Rename values in a vector based on a dictionary

Description

This function provides an interface for forcats::fct_recode(), forcats::fct_explicit_na(), and forcats::fct_relevel() in such a way that a data dictionary can be imported from a data frame.

Usage

match_vec(
  x = character(),
  dictionary = data.frame(),
  from = 1,
  to = 2,
  quiet = FALSE,
  warn_default = TRUE,
  anchor_regex = TRUE
)

Arguments

x

a character or factor vector

dictionary

a matrix or data frame defining mis-spelled words or keys in one column (from) and replacement values (to) in another column. There are keywords that can be appended to the from column for addressing default values and missing data.

from

a column name or position defining words or keys to be replaced

to

a column name or position defining replacement values

quiet

a logical indicating if warnings should be issued if no replacement is made; if FALSE, these warnings will be disabled

warn_default

a logical. When a .default keyword is set and warn_default = TRUE, a warning will be issued listing the variables that were changed to the default value. This can be used to update your dictionary.

anchor_regex

a logical. When TRUE (default), any regex within the keywork

Details

Keys (from column)

The from column of the dictionary will contain the keys that you want to match in your current data set. These are expected to match exactly with the exception of three reserved keywords that start with a full stop:

  • .regex [pattern]: will replace anything matching ⁠[pattern]⁠. This is executed before any other replacements are made. The ⁠[pattern]⁠ should be an unquoted, valid, PERL-flavored regular expression. Any whitespace padding the regular expression is discarded.

  • .missing: replaces any missing values (see NOTE)

  • .default: replaces ALL values that are not defined in the dictionary and are not missing.

Values (to column)

The values will replace their respective keys exactly as they are presented.

There is currently one recognised keyword that can be placed in the to column of your dictionary:

  • .na: Replace keys with missing data. When used in combination with the .missing keyword (in column 1), it can allow you to differentiate between explicit and implicit missing data.

Value

a vector of the same type as x with mis-spelled labels cleaned. Note that factors will be arranged by the order presented in the data dictionary; other levels will appear afterwards.

Note

If there are any missing values in the from column (keys), then they are automatically converted to the character "NA" with a warning. If you want to target missing data with your dictionary, use the .missing keyword. The .regex keyword uses gsub() with the perl = TRUE option for replacement.

Author(s)

Zhian N. Kamvar

See Also

match_df() for an implementation that acts across multiple variables in a data frame.

Examples

corrections <- data.frame(
  bad = c("foubar", "foobr", "fubar", "unknown", ".missing"),
  good = c("foobar", "foobar", "foobar", ".na", "missing"),
  stringsAsFactors = FALSE
)
corrections

# create some fake data
my_data <- c(letters[1:5], sample(corrections$bad[-5], 10, replace = TRUE))
my_data[sample(6:15, 2)] <- NA  # with missing elements

match_vec(my_data, corrections)

# You can use regular expressions to simplify your list
corrections <- data.frame(
  bad =  c(".regex f[ou][^m].+?r$", "unknown", ".missing"),
  good = c("foobar",                ".na",     "missing"),
  stringsAsFactors = FALSE
)

# You can also set a default value
corrections_with_default <- rbind(corrections, c(bad = ".default", good = "unknown"))
corrections_with_default

# a warning will be issued about the data that were converted
match_vec(my_data, corrections_with_default)

# use the warn_default = FALSE, if you are absolutely sure you don't want it.
match_vec(my_data, corrections_with_default, warn_default = FALSE)

# The function will give you a warning if the dictionary does not
# match the data
match_vec(letters, corrections)

# The can be used for translating survey output

words <- data.frame(
  option_code = c(".regex ^[yY][eE]?[sS]?",
    ".regex ^[nN][oO]?",
    ".regex ^[uU][nN]?[kK]?",
    ".missing"),
  option_name = c("Yes", "No", ".na", "Missing"),
  stringsAsFactors = FALSE
)
match_vec(c("Y", "Y", NA, "No", "U", "UNK", "N"), words)

show the path to a matchmaker example file

Description

show the path to a matchmaker example file

Usage

matchmaker_example(name = NULL)

Arguments

name

the name of a matchmaker example file

Value

a path to a matchmaker example file

Author(s)

Zhian N. Kamvar

Examples

matchmaker_example() # list all of the example files

# read in example spelling dictionary
sd <- matchmaker_example("spelling-dictionary.csv")
read.csv(sd, stringsAsFactors = FALSE)

# read in example coded data
coded_data <- matchmaker_example("coded-data.csv")
coded_data <- read.csv(coded_data, stringsAsFactors = FALSE)
str(coded_data)
coded_data$date <- as.Date(coded_data$date)