Name
Regex Substitute
Description
Match a regular expression to the value of a parameter and make replacements as dictated by the substitution. The syntax for the regular expression and substitution follows the Python regular expression library and how to guide.
Fields
Parameter: The name of the parameter to which the regular expression will be applied.
Regex: The expression used to match a subset of the field name values.
Substitution: The expression used to replace the values of the matched regular expression.
Examples
Example A - Replace Student with Learner.
- Input: Student, Assistant
- Regex: Student
- Substitution: Learner
- Result: Learner, Assistant
Example B - Remove a single L if and only if it's the first character in the string.
- Input: LM_BIOL_1010
- Regex: (^[L])(.*)
- Substitution: \2
- Result: M_BIOL_1010
Example C - Replace two periods with underscores.
- Input: bob.john.smith
- Regex: ([^\W.]+).([^\W.]+).([^\W.]+)
- Substitution: \1_\2_\3
- Result: bob_john_smith
Example D - Take an email and remove the domain.
- Input: bsmith@school.edu
- Regex: ([^@]+).(.*)
- Substitution: \1
- Result: bsmith
Example E - Take a course ID of the format Subject-Number-Session.Year.Section separated by hyphens and periods and (1) remove the hyphen between Subject-Number, (2) swap the order of the Year and Session and (3) truncate the sectional information.
- Input: MATH-1010-FA.2017.CRN14820
- Regex: ([^\W-]+).([^\W-]+).([^\W.]+).([^\W.]+).([^\W.]+)
- Substitution: \1\2-\4.\3
- Result: MATH1010-2017.FA
Errors
Errors will occur in the following cases:
- The regex is malformed (e.g. a bracket or parentheses is left open or unbalanced)
- The substitution references an invalid group (e.g. \1_\2_\3 where the Regex only has two groups)
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