6.8 Field Passing

In many data sets there are fields that are already in a cleaned and standardised form, and which therefore can directly be copied into corresponding output fields (so they are available for a linkage or deduplication process later). The simple PassFieldStandardiser can be used for this. It copies the values from the input fields into the corresponding output fields without any modifications. The number of input fields must be the same as the number of output fields. Values in the first input field will be copied into the first output field, values from the second input field into the second output field, and so on. The example code below shows how to apply the field pass standardiser on two fields in a fictitious hospital data set.

The following arguments must be given when a field pass standardiser is initialised.

name
A name for the field pass standardiser. Most suitable is a short string.
description
A longer description of the field pass standardiser. Note that this argument is not mandatory.
input_fields
A string with a field name or a list of field names from the input data set. Values from this input field(s) will be copied into the output field(s). The number of input fields must be the same as the number of output fields.
output_fields
A string with a field name or a list of field names from the output data set. Values from the input field(s) will be copied into this output field(s). The number of output fields must be the same as the number of input fields.

In the example given in the following code block, values from the input field 'ohoscode' are passed (copied) into the output field 'hosp_code', and values from input field 'rseqnum' are copied into output field 'seq_num'.

# ====================================================================

pass_fields = PassFieldStandardiser(name = 'Field passer',
                             description = 'Passes OK fields',
                            input_fields = ['ohoscode',  'rseqnum'],
                           output_fields = ['hosp_code', 'seq_num'])