ure – Regular Expression

2023-08-31

This feature matches data by regular expression.

Currently, only a few operators are supported.

Example

import ure

res = '''
$GNRMC,133648.00,A,3149.2969,N,11706.9027,E,0.055,,311020,,,A,V*18
$GNGGA,133648.00,3149.2969,N,11706.9027,E,1,24,1.03,88.9,M,,M,,*6C
$GNGLL,3149.2969,N,11706.9027,E,133648.00,A,A*7A
$GNGSA,A,3,31,26,11,194,27,195,08,09,03,193,04,16,1.41,1.03,0.97,1*31
'''

r = ure.search("GNGGA(.+?)M", res)
print(r.group(0))

Compile and Generate Regular Expression

ure.compile

ure.compile(regex)

Compiles a regular expression and generates a regular-expression object, used by ure.match() and ure.search().

Parameter

  • regex – String type. A regular expression.

Match Regular Expression

ure.match

ure.match(regex, string)

Matches the compiled regular expression against string. Match always happens from the start position in a string.

Parameter

  • regex – String type. A regular expression.
  • string – The string to be matched.

Return Value

  • A matched object – Successful execution
  • None – Failed execution

Search Regular Expression

ure.search

ure.search(regex, string)

Searches for the compiled regular expression in string and returns the first successful match.

Parameter

  • regex – String type. A regular expression.
  • string – The string in which you search for the compiled regular expression

Return Value

  • A matched object – Successful execution
  • None – Failed execution

Match Single String

match.group

match.group(index)

Matches objects as returned by ure.match() and ure.search().

Parameter

  • index – Integer type. The index of the groups of the match. In a regular expression, match.group() proposes the string captured by grouping. index is 0 for the entire match. index is captured by the compiled regular expression and an error occurs when the group does not exist.

Return Value

  • The string matching the entire regular expression.

Constants

Supported Operators

  • ‘.’ – Character type. Match any character.
  • ‘[]’ – Character type. Match set of characters. Individual characters and ranges are supported, including negated sets.
  • ‘^’ – Character type. Match the start of the string.
  • ‘$’ – Character type. Match the end of the string.
  • ‘?’ – Character type. Match zero or one of the previous sub-pattern.
  • ‘*’ – Character type. Match zero or more of the previous sub-pattern.
  • ‘+’ – Character type. Match one or more of the previous sub-pattern.
  • ‘??’ – Character type. Non-greedy version of ?, match zero or one.
  • ‘*?’ – Character type. Non-greedy version of *, match zero or more.
  • ‘+?’ – Character type. Non-greedy version of +, match one or more.
  • ‘\|’ – Character type. Match either the left-hand side or the right-hand side sub-patterns of this operator.
  • ‘\d’ – Character type. Match digit.
  • ‘\D’ – Character type. Match non-digit.
  • ‘\s’ – Character type. Match whitespace.
  • ‘\S’ – Character type. Match non-whitespace.
  • ‘\w’ – Character type. Match "word characters" (ASCII only).
  • ‘\W’ – Character type. Match "word characters" (ASCII only).

Not Supported Operators

  • ‘{m,n}’ – Counted repetitions.
  • ‘(?P<name>...)’ – Named groups.
  • ‘(?:...)’ – Non-capturing groups.
  • ‘\b’ – More advanced assertions.
  • ‘\B’ – More advanced assertions.
  • ‘\r’ – Special character escapes – use Python’s own escaping instead.
  • ‘\n’ – Special character escapes – use Python’s own escaping instead.