[
https://issues.apache.org/jira/browse/BEAM-7018?focusedWorklogId=281146&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-281146
]
ASF GitHub Bot logged work on BEAM-7018:
----------------------------------------
Author: ASF GitHub Bot
Created on: 23/Jul/19 16:59
Start Date: 23/Jul/19 16:59
Worklog Time Spent: 10m
Work Description: mszb commented on pull request #8859: [BEAM-7018] Added
Regex transform for PythonSDK
URL: https://github.com/apache/beam/pull/8859#discussion_r306429138
##########
File path: sdks/python/apache_beam/transforms/util.py
##########
@@ -864,3 +867,223 @@ def add_window_info(element,
timestamp=DoFn.TimestampParam,
def expand(self, pcoll):
return pcoll | ParDo(self.add_window_info)
+
+
+class Regex(object):
+ """
+ PTransform to use Regular Expression to process the elements in a
+ PCollection.
+ """
+ @staticmethod
+ def _regex_compile(regex):
+ """Return re.compile if the regex has a string value"""
+ if isinstance(regex, str):
+ regex = re.compile(regex)
+ return regex
+
+ @staticmethod
+ @typehints.with_input_types(str)
+ @typehints.with_output_types(str)
+ @ptransform_fn
+ def matches(pcoll, regex, group=0):
+ """
+ Returns the matches if the element matched the Regex. Returns the
+ entire line (group 0 by default). Group can be integer value or a string
+ value.
+
+ Args:
+ regex: the regular expression string or (re.compile) pattern.
+ group: (optional) name/number of the group, it can be integer or a string
+ value.
+ """
+ regex = Regex._regex_compile(regex)
+
+ def _process(element):
+ m = regex.match(element)
+ if m:
+ yield m.group(group)
+ return pcoll | FlatMap(_process)
+
+ @staticmethod
+ @typehints.with_input_types(str)
+ @typehints.with_output_types(str)
+ @ptransform_fn
+ def all_matches(pcoll, regex):
+ """
+ Returns the matches if the entire line matches the Regex. Returns all
+ groups.
+
+ Args:
+ regex: the regular expression string or (re.compile) pattern.
+ """
+ regex = Regex._regex_compile(regex)
+
+ def _process(element):
+ m = regex.match(element)
+ results = list()
+
+ if m:
+ results.append(m.group())
+ for match in m.groups():
+ results.append(match)
+ if results:
+ yield results
+ return pcoll | FlatMap(_process)
+
+ @staticmethod
+ @typehints.with_input_types(str)
+ @typehints.with_output_types(typehints.KV[str, str])
+ @ptransform_fn
+ def matches_kv(pcoll, regex, keyGroup, valueGroup):
+ """
+ Returns the KV pairs if the string matches the regular expression, deriving
+ the key & value from the specified group of the regular expression.
+
+ Args:
+ regex: the regular expression string or (re.compile) pattern.
+ keyGroup: The Regex group to use as the key. Can be int or str.
+ valueGroup: The Regex group to use the value. Can be int or str.
+ """
+ regex = Regex._regex_compile(regex)
+
+ def _process(element):
+ match = regex.match(element)
+ if match:
+ yield (match.group(keyGroup), match.group(valueGroup))
+ return pcoll | FlatMap(_process)
+
+ @staticmethod
+ @typehints.with_input_types(str)
+ @typehints.with_output_types(str)
+ @ptransform_fn
+ def find(pcoll, regex, group=0):
+ """
+ Returns the matches if a portion of the line matches the Regex. Returns
+ the entire group (group 0 by default). Group can be integer value or a
+ string value.
+
+ Args:
+ regex: the regular expression string or (re.compile) pattern.
+ group: (optional) name of the group, it can be integer or a string value.
+ """
+ regex = Regex._regex_compile(regex)
+
+ def _process(element):
+ r = regex.search(element)
+ if r:
+ yield r.group(group)
+ return pcoll | FlatMap(_process)
+
+ @staticmethod
+ @typehints.with_input_types(str)
+ @typehints.with_output_types(str)
+ @ptransform_fn
+ def find_all(pcoll, regex):
+ """
+ Returns the matches if a portion of the line matches the Regex. Returns all
+ the groups as a List of string.
+
+ Args:
+ regex: the regular expression string or (re.compile) pattern.
+ """
+ regex = Regex._regex_compile(regex)
+
+ def _process(element):
+ m = regex.finditer(element)
+ results = list()
+ for match in m:
+ results.append(match.group())
+ for groupNum in range(0, len(match.groups())):
+ results.append(match.group(groupNum + 1))
+ if results:
+ yield results
+ return pcoll | FlatMap(_process)
+
+ @staticmethod
+ @typehints.with_input_types(str)
+ @typehints.with_output_types(typehints.KV[str, str])
+ @ptransform_fn
+ def find_kv(pcoll, regex, keyGroup, valueGroup):
+ """
+ Returns the matches if a portion of the line matches the Regex. Returns the
+ specified groups as the key and value pair.
+
+ Args:
+ regex: the regular expression string or (re.compile) pattern.
+ keyGroup: The Regex group to use as the key. Can be int or str.
+ valueGroup: The Regex group to use the value. Can be int or str.
+ """
+ regex = Regex._regex_compile(regex)
+
+ def _process(element):
+ matches = regex.finditer(element)
+ if matches:
+ for match in matches:
+ yield (match.group(keyGroup), match.group(valueGroup))
+
+ return pcoll | FlatMap(_process)
+
+ @staticmethod
+ @typehints.with_input_types(str)
+ @typehints.with_output_types(str)
+ @ptransform_fn
+ def replace_all(pcoll, regex, replacement):
+ """
+ Returns the matches if a portion of the line matches the Regex and
+ replaces all matches with the replacement String.
+
+ Args:
+ regex: the regular expression string or (re.compile) pattern.
+ replacement: the string to be substituted for each match.
+ """
+ regex = Regex._regex_compile(regex)
+
+ def _process(element):
+ yield regex.sub(replacement, element)
+
+ return pcoll | FlatMap(_process)
+
+ @staticmethod
+ @typehints.with_input_types(str)
+ @typehints.with_output_types(str)
+ @ptransform_fn
+ def replace_first(pcoll, regex, replacement):
+ """
+ Returns the matches if a portion of the line matches the Regex and replaces
+ the first match with the replacement String.
+
+ Args:
+ regex: the regular expression string or (re.compile) pattern.
+ replacement: the string to be substituted for each match.
+ """
+ regex = Regex._regex_compile(regex)
+
+ def _process(element):
+ yield regex.sub(replacement, element, 1)
+
+ return pcoll | FlatMap(_process)
+
+ @staticmethod
+ @typehints.with_input_types(str)
+ @typehints.with_output_types(str)
+ @ptransform_fn
+ def split(pcoll, regex, outputEmpty=False):
+ """
+ Returns the list of string which was splitted on the basis of regular
+ expression and then outputs each item. It will not output empty items.
+
+ Args:
+ regex: the regular expression string or (re.compile) pattern.
+ outputEmpty: (optional) Should empty be output. True to output empties
+ and false if not.
+ """
+ regex = Regex._regex_compile(regex)
+ outputEmpty = bool(outputEmpty)
+
+ def _process(element):
+ r = regex.split(element)
+ if r and not outputEmpty:
+ r = list(filter(None, r))
+ yield r
Review comment:
Fix the type hints to `typehints.List[str]`. I think it's better to get
results of each collection item rather then flattens them all. Your thoughts?
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Issue Time Tracking
-------------------
Worklog Id: (was: 281146)
Time Spent: 9h (was: 8h 50m)
> Regex transform for Python SDK
> ------------------------------
>
> Key: BEAM-7018
> URL: https://issues.apache.org/jira/browse/BEAM-7018
> Project: Beam
> Issue Type: New Feature
> Components: sdk-py-core
> Reporter: Rose Nguyen
> Assignee: Shehzaad Nakhoda
> Priority: Minor
> Time Spent: 9h
> Remaining Estimate: 0h
>
> PTransorms to use Regular Expressions to process elements in a PCollection
> It should offer the same API as its Java counterpart:
> [https://github.com/apache/beam/blob/11a977b8b26eff2274d706541127c19dc93131a2/sdks/java/core/src/main/java/org/apache/beam/sdk/transforms/Regex.java]
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