Split String Based on Regex

How to split strings using regular expressions

Actually this is easy enough to just use match :

string subjectString = @"green,""yellow,green"",white,orange,""blue,black""";
try
{
    Regex regexObj = new Regex(@"(?<="")\b[a-z,]+\b(?="")|[a-z]+", RegexOptions.IgnoreCase);
    Match matchResults = regexObj.Match(subjectString);
    while (matchResults.Success)
    {
        Console.WriteLine("{0}", matchResults.Value);
        // matched text: matchResults.Value
        // match start: matchResults.Index
        // match length: matchResults.Length
        matchResults = matchResults.NextMatch();
    }
}

Output :

green
yellow,green
white
orange
blue,black

Explanation :

@"
             # Match either the regular expression below (attempting the next alternative only if this one fails)
   (?<=         # Assert that the regex below can be matched, with the match ending at this position (positive lookbehind)
      ""            # Match the character “""” literally
   )
   \b           # Assert position at a word boundary
   [a-z,]       # Match a single character present in the list below
                   # A character in the range between “a” and “z”
                   # The character “,”
      +            # Between one and unlimited times, as many times as possible, giving back as needed (greedy)
   \b           # Assert position at a word boundary
   (?=          # Assert that the regex below can be matched, starting at this position (positive lookahead)
      ""            # Match the character “""” literally
   )
|            # Or match regular expression number 2 below (the entire match attempt fails if this one fails to match)
   [a-z]        # Match a single character in the range between “a” and “z”
      +            # Between one and unlimited times, as many times as possible, giving back as needed (greedy)
"

Split String based on multiple Regex matches

The matching changes because:

• In the first part, you call .group().split() where .group() returns the full match which is a string.

• In the second part, you call re.compile("...").split() where re.compile returns a regular expression object.

In the pattern, this part will match only a single word [a-zA-Z0-9]+[ ], and if this part should be in a capture group [0-9]([-][0-9]+)? the first (single) digit is currently not part of the capture group.

You could write the pattern writing 4 capture groups:

^(.*? )?((?:[Ll]ist|[Tt]able|[Ff]igure))\s+(\d+(?:-\d+)?):\s+(.+)

See a regex demo.

import re

pattern = r"^(.*? )?((?:[Ll]ist|[Tt]able|[Ff]igure))\s+(\d+(?:-\d+)?):\s+(.+)"
s = "Text Table 6-2:    Management of children study and actions"
m = re.match(pattern, s)
if m:
    print(m.groups())

Output

('Text ', 'Table', '6-2', 'Management of children study and actions')

---

If you want point 1 and 2 as one string, then you can use 2 capture groups instead.

^((?:.*? )?(?:[Ll]ist|[Tt]able|[Ff]igure)\s+\d+(?:-\d+)?):\s+(.+)

Regex demo

The output will be

('Text Table 6-2', 'Management of children study and actions')

How to split a string based on two regex formats?

The problem is that String.split() gives you only the pieces between delimiters. The delimiters themselves -- the substrings that match the pattern -- are omitted. But you don't have actual delimiters in your string. Rather, you want to split at transitions between digits and non-digits. These can be matched via zero-width assertions:

string.split("(?<![0-9])(?=[0-9])|(?<=[0-9])(?![0-9])");

That is

• the position after a non-digit (?<![0-9]) and before a digit (?=[0-9])

or (|)

• the position after a digit (?<=[0-9]) and before a non-digit (?![0-9])

Split string based on regex

I suggest

l = re.compile("(?<!^)\s+(?=[A-Z])(?!.\s)").split(s)

Check this demo.

Splitting strings based on regex expression

# If the string matches a certain pattern, split it in two.
[array] $tokens = 
 if ($str -match '^(\d{3})([a-z]\d)$') { $Matches.1, $Matches.2 }
 else                                  { $str }

# Test if all tokens exist as elements in the array.
# -> $true, in this case.
$allTokensContainedInArray = 
  (Compare-Object $array $tokens).SideIndicator -notcontains '=>'

• The regex-based -match operator is used to test whether $str starts with 3 digits, followed by a letter and a single digit, and, if so, via capture groups ((...)) and the automatic $Matches variable, splits the string into the part with the 3 digits and the rest.

• The above uses Compare-Object to test (case-insensitively) if the array elements derived from the input string are all contained in the reference array, in any order, while allowing the reference array to contain additional elements.

---

If you want to limit all input strings to those matching regex pattern, before even attempting lookup in the array:

# If no pattern matches, $tokens will be $null
[array] $tokens = 
  if     ($str -match '^(\d{3})([a-z]\d)$') { $Matches.1, $Matches.2 }
  elseif ($str -match '^\d{3}$')            { $str }
  elseif ($str -match '^[a-z]\d$')          { $str }

Split string based on a regular expression

By using (,), you are capturing the group, if you simply remove them you will not have this problem.

>>> str1 = "a    b     c      d"
>>> re.split(" +", str1)
['a', 'b', 'c', 'd']

However there is no need for regex, str.split without any delimiter specified will split this by whitespace for you. This would be the best way in this case.

>>> str1.split()
['a', 'b', 'c', 'd']

If you really wanted regex you can use this ('\s' represents whitespace and it's clearer):

>>> re.split("\s+", str1)
['a', 'b', 'c', 'd']

or you can find all non-whitespace characters

>>> re.findall(r'\S+',str1)
['a', 'b', 'c', 'd']

split string with RegEx pattern with words and numbers

By just adding twice (?:\s) to your expression:

re.findall(r"(?:^|(?<=\d\.))(?:\s)([\sa-zA-Z0-9]+)(?:\s\d\.|$)", test_string)

the output is : ['Fruit 12 oranges', 'vegetables 7 carrot', 'NFL 246 SHIRTS']

JavaScript split string with .match(regex)

Use a non-capturing group as split regex. By using non-capturing group, split matches will not be included in resulting array.

var string4 = 'one split two splat three splot four';var splitString4 = string4.split(/\s+(?:split|splat|splot)\s+/);console.log(splitString4);

Splitting a string by a regular expression

Yes, a regex can easily do this :)

# SELECT regexp_split_to_table(
    'I use Python, SQL, C++. I need: apples and oranges',
    '[ .,:;]+');
┌───────────────────────┐
│ regexp_split_to_table │
├───────────────────────┤
│ I                     │
│ use                   │
│ Python                │
│ SQL                   │
│ C++                   │
│ I                     │
│ need                  │
│ apples                │
│ and                   │
│ oranges               │
└───────────────────────┘
(10 rows)

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