I am looking for a way to split PascalCase strings, e.g. "MyString", into separate words - "My", "String". Another user posed the question for bash, but I want to know how to do it with general regular expressions or at least in .NET.
Bonus if you can find a way to also split (and optionally capitalize) camelCase strings: e.g. "myString" becomes "my" and "String", with the option to capitalize/lowercase either or both of the strings.
var regex = new Regex("([A-Z]+[^A-Z]+)");
var matches = regex.Matches("aCamelCaseWord")
.Cast<Match>()
.Select(match => match.Value);
foreach (var element in matches)
{
Console.WriteLine(element);
}
Prints
Camel
Case
Word
(As you can see, it doesn't handle camelCase - it dropped the leading "a".)
Check that a non-word character comes at the beginning of your regex with \W and keep the individual strings together, then split the words.
Something like: \W([A-Z][A-Za-z]+)+
For: sdcsds sd aCamelCaseWord as dasd as aSscdcacdcdc PascelCase DfsadSsdd sd
Outputs:
48: PascelCase
59: DfsadSsdd
In Ruby:
"aCamelCaseWord".split /(?=[[:upper:]])/
=> ["a", "Camel", "Case", "Word"]
I'm using positive lookahead here, so that I can split the string right before each uppercase letter. This lets me save any initial lowercase part as well.
Answered in a different question:
void Main()
{
"aCamelCaseWord".ToFriendlyCase().Dump();
}
public static class Extensions
{
public static string ToFriendlyCase(this string PascalString)
{
return Regex.Replace(PascalString, "(?!^)([A-Z])", " $1");
}
}
Outputs a Camel Case Word (.Dump() just prints to the console).
See this question: Is there a elegant way to parse a word and add spaces before capital letters? Its accepted answer covers what you want, including numbers and several uppercase letters in a row. While this sample has words starting in uppercase, it it equally valid when the first word is in lowercase.
string[] tests = {
"AutomaticTrackingSystem",
"XMLEditor",
"AnXMLAndXSLT2.0Tool",
};
Regex r = new Regex(
@"(?<=[A-Z])(?=[A-Z][a-z])|(?<=[^A-Z])(?=[A-Z])|(?<=[A-Za-z])(?=[^A-Za-z])"
);
foreach (string s in tests)
r.Replace(s, " ");
The above will output:
[Automatic][Tracking][System]
[XML][Editor]
[An][XML][And][XSLT][2.0][Tool]
How about:
static IEnumerable<string> SplitPascalCase(this string text)
{
var sb = new StringBuilder();
using (var reader = new StringReader(text))
{
while (reader.Peek() != -1)
{
char c = (char)reader.Read();
if (char.IsUpper(c) && sb.Length > 0)
{
yield return sb.ToString();
sb.Length = 0;
}
sb.Append(c);
}
}
if (sb.Length > 0)
yield return sb.ToString();
}