Pattern Matching using Regular Expressions

Search String

Description

Example

A simple string of letters or numbers

Simple String. A RegEx expression of simple letters or numbers will pattern match specific phrases or words.

The search string “Number” will match the first occurrence of the word “Number” on the scanned document (or all occurrences of “number” into a Multi-Value Field).

(?i)

Case Sensitivity. Pattern matching is case sensitive by default. To create a case-insensitive search, add the modifier “(?i)” to the beginning of the string.

Multi-line search string

Sequence Based on Priority. A search string of multiple lines can instruct the Template to search for different words or phrases in a specific order of priority.

This pattern logic can be used in cases where the content of a document or region can take multiple forms. Using a sequence based on priority, pattern matching enables you to anticipate multiple scenarios of incoming data and adapt the behavior step by step.

The Template attempts to match “following” first. Since a match is found, it does not continue on to match “number.”

In a case where the first line fails to match, the Template matches “number” on its second pass.

.

Wildcard. Many characters hold special meaning in RegEx syntax. A period is used as a wildcard to match any character or number in the document. This can be used create patterns that match a variety of different phrases or words with fuzzy logic.

The search string “Attn: …..” will match both “Attn: Scott” and “Attn: Abita.”

\

Escape Character. In cases where you want to use a special character literally, you must strip its special meaning with an escape character. In RegEx, a backslash is used to invoke this alternate interpretation.

|

Logical Operator. Logical operators allow pattern matching an extra degree of complexity. The pipe character signifies a logical OR operator.

A search string “Somehow|Court” will return matches for either of the words “Somehow” and “Court.”

[a|b]

Character Range a or b. In addition to literal characters and wildcards, search strings can detect groups of characters using character ranges and logical operators.

The search string “[P|M]al[e|t]” detects a word which: begins with either a “P” or an “M”; followed by “al”; and ends with either an “e” or a “t.” When checked against the sample document, this pattern matches both ”Pale” and “Malt.”

[abc]

Character Range a or b or c. A search string to detect this OR this OR that.

A search string “[BCH]at” will match “Bat,” “Cat,” and “Hat.”

[^abc]

Character Range Not a or b or c. A search string to detect characters which are not this OR this OR that.

The search string “[^A]” will match any character except capital A.

[0-9]

Character Range 0 to 9. A search string to detect a range of digits between 0 and 9.

The search string “[0-9]” will match any one digit.

[a-z]

Character Range in Lowercase Letters. A search string to detect letters in a range with lowercase letters.

The search string containing “[a-z]” will match any one lowercase letter.

[a-z|A-Z]

Character Range in Both Uppercase and Lowercase Letters. A search string to detect letters in a range, regardless of the letter case.

The search string containing “[a-z|A-Z]” will match any letter of the alphabet, whether uppercase or lowercase.

*

0 or More Quantifier. Quantifiers are used to specify how many instances of a character or string are required to produce a match. Use an asterisk to search for a range of none to unlimited.

The search string containing “7*” will match 0 to infinite 7’s.

c+

1 or More Quantifier. Use a plus sign to search for a range of one to unlimited number or characters or strings.

The search string containing “Z+” will match 1 to infinite Z’s

?

0 or 1 Quantifier. Use a question mark to search for a range of none or one characters or strings.

The search string containing “colou?r,” will return matches for either of the words “color” or “colour.”

{#}

Exactly the Specified Number Quantifier. Use a number surrounded by braces to search for a specific quantify of characters or strings.

The search string containing “7{3}” detects three sevens in a row.

{#,}

Exactly the Specified Number or More Quantifier. Use a number, followed by a comma, and surrounded by braces to search for a specific quantify or more of characters or strings.

The search string containing “Z{3,}” detects three to infinite Z’s.

{#,#}

Exactly the Specified Number or More Quantifier. Use a number, comma, number, surrounded by braces to search for characters or strings between the first number and the next.

The search string containing “Z{3,5}” detects three to five Z’s.

[0-9]{#}

Number with Specific Digits and Amounts of Digits. Use a combination of Character Range 0 to 9 and Exactly the Specified Number Quantifier to search for specific patterns of digits.

The pattern “[0-9]{8}" matches any eight digits in a row, such as an eight-digit purchase order number.

[A-Z]{#} [0-9]{#}

Compound Combinations of Letters and Digits. Use a series of RegEx sequences of characters to create very specific or for very general (“robust”) search patterns.

To search for U.S.A. addresses, the pattern “[A-Z]{2} [0-9]{5}” matches a state code plus a ZIP code (two uppercase letters followed by a space and then a five-digit number).

[0-9]{3}\.[0-9]{3}]\.[0-9]{4}

Compound Combinations with Escape Characters. Use a series of RegEx sequences of characters, including ones which use a special character literally.

The pattern “[0-9]{3}\.[0-9]{3}]\.[0-9]{4}” matches a seven-digit phone number plus area code, separated by periods. Note that escape characters are required.

(([\w]+[-._+&])*[\w]+@([-\w]+[.])+[a-zA-Z]{2,6})

Diversity and Robustness of Pattern Matching. Pattern Matching with RegEx is an extremely powerful tool. With a good understanding of its syntax, the possibilities are endless.

“(([\w]+[-._+&])*[\w]+@([-\w]+[.])+[a-zA-Z]{2,6})” will match valid email addresses of various forms.