write_fwf_blaise_with_model {blaise}

Write a fixed width ascii datafile based on a given blaise datamodel

Description

Write a datafile in the blaise format (fwf ascii without separators) using an existing datamodel. will not write out a datamodel unless explicitly asked to. Tries to automatically match colummns by name using Levenshtein distance and will change types if required and possible.

Usage

write_fwf_blaise_with_model(
  df,
  output_data,
  input_model,
  output_model = NULL,
  decimal.mark = ".",
  digits = getOption("digits"),
  justify = "right",
  max.distance = 0L
)

Arguments

df

dataframe to write

output_data

path and name to output datafile. Will add .asc if no extension

input_model

the datamodel used to convert the dataframe and write the output

output_model

path and name to output datamodel. If NULL will not write anything. default is NULL

decimal.mark

decimal mark to use. Default is ".".

digits

how many significant digits are to be used for numeric vectors. The default uses getOption("digits"). This is a suggestion: enough decimal places will be used so that the smallest (in magnitude) number has this many significant digits.

justify

direction of padding for STRING type when data is smaller than the width. Defaults to right-justified (padded on the left), can be "left", "right" or "centre".

max.distance

maximum Levenshtein distance to match columns. ignores case changes. Set to 0 (default) to only accept exact matches ignoring case. 4 appears to be a good number in general. Will prevent double matches and will pick te best match for each variable in the datamodel.

Value

output as it is written to file as a character vector. Does so invisibly, will not print but can be assigned.

Examples

datafilename = tempfile('testdata', fileext = '.asc')
blafilename = tempfile('testbla', fileext = '.bla')

model = "
DATAMODEL Test
FIELDS
A     : STRING[1]
B     : INTEGER[1]
C     : REAL[3,1]
D     : REAL[3]
E     : (Male, Female)
F     : 1..20
G     : 1.00..100.00
H     : DATETYPE
ENDMODEL
"
writeLines(model, con = blafilename)

  df = data.frame(
list(
  A = rep('t',3),
  B = 1:3,
  C = 1.1:3.3,
  D = 1.0:3.0,
  E = factor(c(1,2,1), labels = c('Male', 'Female')),
  F = 1:3,
  G = c(1., 99.9, 78.5),
  H = as.Date(rep('2001-01-01', 3))
)
)
write_fwf_blaise_with_model(df, datafilename, blafilename)


model = "
DATAMODEL Test
FIELDS
A     : STRING[1]
B     : STRING[1]
C     : STRING[3]
E     : STRING[1]
H     : STRING[8]
ENDMODEL
"
writeLines(model, con = blafilename)

df = data.frame(
list(
A = rep('t',3),
E = factor(c(1,2,1), labels = c('Male', 'Female')),
B = 1:3,
C = 1.1:3.3,
H = as.Date(rep('2001-01-01', 3))
),
stringsAsFactors = FALSE
)
write_fwf_blaise_with_model(df, datafilename, blafilename)