String split with spaces using regex - regex

Question

I am trying to split a string using regex. I need to use regex in nifi to split a string into groups. Could anyone helps me how to split below string using regex.
or how can we give specific occurrence number of delimiter to split the string. For example in the below string how can I specify that I want a string after 3rd occurrence of space.
Suppose i have a String
"6/19/2017 12:14:07 PM 0FA0 PACKET 0000000DF5EC3D80 UDP Snd 11.222.333.44 93c8 R Q [8085 A DR NOERROR] PTR (2)73(3)191(3)250(2)10(7)in-addr(4)arpa(0)"
And I want result something like this :
group 1 - 6/19/2017 12:14:07 PM
group 2 - 0FA0
group 3 - PACKET 0000000DF5EC3D80
group 4 - UDP
group 5 - Snd
group 6 - 11.222.333.44
group 7 - 93c8
group 8 - R Q [8085 A DR NOERROR] PTR (2)73(3)191(3)250(2)10(7)in-
addr(4)arpa(0)
Could anyone help me. Thanks in advance.

Answer 1

If it's really just certain spaces you want to have for delimiters you can do something like this to avoid a fixed width nightmare:
regex = "(\S+\s\S+\s\S+)\s(\S+)\s(\S+\s\S+)\s(\S+)\s(\S+)\s(\S+)\s(\S+)\s(.*)"
Pretty much it's what it looks like, groups of NON spaces \S+ with spaces \s and each is grouped with parans. The .* at the end is just the rest of the line, it can be adjusted as needed. If you wanted each group to be every non spaced group you can do a split instead of regex, but it looks like that isn't what is desired. I don't have access to nifi to test, but here is an example in Python.
import re
text = "6/19/2017 12:14:07 PM 0FA0 PACKET 0000000DF5EC3D80 UDP Snd 11.222.333.44 93c8 R Q [8085 A DR NOERROR] PTR (2)73(3)191(3)250(2)10(7)in-addr(4)arpa(0)"
regex = "(\S+\s\S+\s\S+)\s(\S+)\s(\S+\s\S+)\s(\S+)\s(\S+)\s(\S+)\s(\S+)\s(.*)"
match = re.search(regex, text)
print ("group 1 - " + match.group(1))
print ("group 2 - " + match.group(2))
print ("group 3 - " + match.group(3))
print ("group 4 - " + match.group(4))
print ("group 5 - " + match.group(5))
print ("group 6 - " + match.group(6))
print ("group 7 - " + match.group(7))
print ("group 8 - " + match.group(8))
Output:
group 1 - 6/19/2017 12:14:07 PM
group 2 - 0FA0
group 3 - PACKET 0000000DF5EC3D80
group 4 - UDP
group 5 - Snd
group 6 - 11.222.333.44
group 7 - 93c8
group 8 - R Q [8085 A DR NOERROR] PTR (2)73(3)191(3)250(2)10(7)in-addr(4)arpa(0)

Answer 2

Are you trying to extract every group into a separate attribute? This is certainly possible in "pure" NiFi, but with lines this long, it may make more sense to use ExecuteScript processor to use Groovy or Python's more complex regular expression handling in conjunction with String#split() and provide a script like sniperd posted.
To perform this task using ExtractText, you'll configure it as follows:
Copyable patterns:
group 1: (^\S+\s\S+\s\S+)
group 2: (?i)(?<=\s)([a-f0-9]{4})(?=\s)
group 3: (?i)(?<=\s)(PACKET\s[a-f0-9]{4,16})(?=\s)
group 4: (?i)(?<=\s\S{16}\s)([\w]{3,})(?=\s)
group 5: (?i)(?<=\s.{3}\s)([\w]{3,})(?=\s)
group 6: (?i)(?<=\s.{3}\s)([\d\.]{7,15})(?=\s)
group 7: (?i)(?<=\d\s)([a-f0-9]{4})(?=\s)
group 8: (?i)(?<=\d\s[a-f0-9]{4}\s)(.*)$
It is important to note that Include Capture Group 0 is set to false. You will get duplicate groups (group 1 and group 1.1) due to the way regex expressions are validated in NiFi (currently all regexes must have at least one capture group -- this will be fixed with NIFI-4095 | ExtractText should not require a capture group in every regular expression).
The resulting flowfile has the attributes properly populated:
Full log output:
2017-06-20 14:45:57,050 INFO [Timer-Driven Process Thread-9] o.a.n.processors.standard.LogAttribute LogAttribute[id=c6b04310-015c-1000-b21e-c64aec5b035e] logging for flow file StandardFlowFileRecord[uuid=5209cc65-08fe-44a4-be96-9f9f58ed2490,claim=StandardContentClaim [resourceClaim=StandardResourceClaim[id=1497984255809-1, container=default, section=1], offset=444, length=148],offset=0,name=1920315756631364,size=148]
--------------------------------------------------
Standard FlowFile Attributes
Key: 'entryDate'
Value: 'Tue Jun 20 14:45:10 EDT 2017'
Key: 'lineageStartDate'
Value: 'Tue Jun 20 14:45:10 EDT 2017'
Key: 'fileSize'
Value: '148'
FlowFile Attribute Map Content
Key: 'filename'
Value: '1920315756631364'
Key: 'group 1'
Value: '6/19/2017 12:14:07 PM'
Key: 'group 1.1'
Value: '6/19/2017 12:14:07 PM'
Key: 'group 2'
Value: '0FA0'
Key: 'group 2.1'
Value: '0FA0'
Key: 'group 3'
Value: 'PACKET 0000000DF5EC3D80'
Key: 'group 3.1'
Value: 'PACKET 0000000DF5EC3D80'
Key: 'group 4'
Value: 'UDP'
Key: 'group 4.1'
Value: 'UDP'
Key: 'group 5'
Value: 'Snd'
Key: 'group 5.1'
Value: 'Snd'
Key: 'group 6'
Value: '11.222.333.44'
Key: 'group 6.1'
Value: '11.222.333.44'
Key: 'group 7'
Value: '93c8'
Key: 'group 7.1'
Value: '93c8'
Key: 'group 8'
Value: 'R Q [8085 A DR NOERROR] PTR (2)73(3)191(3)250(2)10(7)in-addr(4)arpa(0)'
Key: 'group 8.1'
Value: 'R Q [8085 A DR NOERROR] PTR (2)73(3)191(3)250(2)10(7)in-addr(4)arpa(0)'
Key: 'path'
Value: './'
Key: 'uuid'
Value: '5209cc65-08fe-44a4-be96-9f9f58ed2490'
--------------------------------------------------
6/19/2017 12:14:07 PM 0FA0 PACKET 0000000DF5EC3D80 UDP Snd 11.222.333.44 93c8 R Q [8085 A DR NOERROR] PTR (2)73(3)191(3)250(2)10(7)in-addr(4)arpa(0)
Another option with the release of NiFi 1.3.0 is to use the record processing capabilities. This is a new feature which allows arbitrary input formats (Avro, JSON, CSV, etc.) to be parsed and manipulated in a streaming manner. Mark Payne has written a very good tutorial here that introduces the feature and provides some simple walkthroughs.