Using regex to match a specific pattern in Python

Question

I am trying to create regex that matches the following pattern:

Note : x is a number e.g. 2

Pattern:

u'id': u'x'                # x = Any Number e.g: u'id': u'2'

So far I have tried the folllowing:

Regex = re.findall(r"'(u'id':u\d)'", Data)

However, no matches are being found.

Try: r"u'id'\s*:\s*u'\d+'"

anubhava
– anubhava

2016-09-23 11:39:48 +00:00
Commented Sep 23, 2016 at 11:39 — anubhava
– anubhava, Commented Sep 23, 2016 at 11:39

anubhava · Accepted Answer · 2016-09-23 11:41:37Z

2

You have misplaced single quotes and you should use \d+ instead of just \d:

>>> s = "u'id': u'2'"
>>> re.findall(r"u'id'\s*:\s*u'\d+'", s)
["u'id': u'2'"]

answered Sep 23, 2016 at 11:41

anubhava

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2 Comments

anubhava Over a year ago

\s* matches 0 or more whitespaces. Double quotes or single quotes around the regex is needed as regex is of string type. Here since single quote is part of the regex itself we need to use double quote for regex string constant.

Enigmatic Over a year ago

I wish I could tell you - think I was scrolling through old questions. Must have been a misclick :D

Simon PA · Accepted Answer · 2016-09-23 12:49:18Z

2

This regex will match your patterns:

u'id': u'(\d+)'

The important bits of the regex here are:

the brackets () which makes a capture group (so you can get the information
the digit marker \d which specifies any digit 0 - 9
the multiple marker + which means "at least 1"

Tested on the following patterns:

u'id': u'3'
u'id': u'20'
u'id': u'250'
u'id': u'6132838'

edited Sep 23, 2016 at 12:49

Simon PA

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answered Sep 23, 2016 at 11:41

James Monger

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Comments

Sunny Aggarwal · Accepted Answer · 2016-09-23 17:04:54Z

1

Try this:

str1 = "u'id': u'x'"

re.findall(r'u\'id\': u\'\d+\'',str1)

You need to escape single-quote(') because it's a special character

edited Sep 23, 2016 at 17:04

answered Sep 23, 2016 at 11:47

Sunny Aggarwal

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3 Comments

Wombatz Over a year ago

Why escape single quotes when you can use double quotes? And please never redefine built-in identifiers like str.

Sunny Aggarwal Over a year ago

@Wombatz sorry I have edit string name but it's a good practice to escape single-quote(') because it needs to be escaped if we use r' ' instead of r" "

Wombatz Over a year ago

If you use r" " you don't have to escape anything.

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