C#•3y ago

✅ Split string on list of strings and on whathever number

Hi, I need to split a string in substrings, splitting every time I find some specific strings (e.g. ">>>") and everytime I find a number of whathever length. I can successfully split on any of the specified string, but I cannot do it with numbers. My C# code is the following:

string value = "545: hello world: <<<example text 567 king's choice>>>";

string[] separators = new string[] {||
    "<<<", 
    ">>>", 
    ":"
}

string[] substrings = value.Split(separators, StringSplitOptions.TrimEntries);

string value = "545: hello world: <<<example text 567 king's choice>>>";

string[] separators = new string[] {||
    "<<<", 
    ">>>", 
    ":"
}

string[] substrings = value.Split(separators, StringSplitOptions.TrimEntries);

I've tried with Regex.split as well but it includes all kind of characters, so I think it's not supposed to be used like that (https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.split?view=net-7.0).

Regex.Split Method (System.Text.RegularExpressions)

Splits an input string into an array of substrings at the positions defined by a regular expression match.

15 Replies

ero•3y ago

Can you show what you've tried? And the desired outcome?

alkasel#159OP•3y ago

Ok. Let's assume I have the string "0: standby" (it is generated by an external program and I need to translate only the relevant parts of it). I'm trying the following approach:

string[] separators = new string[] {
    @"} SPACEFILL DP",
    @"} ZEROFILL DP",
    @":",
    @"'\%s'", 
    @"\%s'", 
    @"<<<<", 
    @"<<<", 
    @"<<", 
    @"<",
    @">>>>", 
    @">>>",
    @">>",
    @">",
    @"system\\User", 
    @"{S_NomeRicetta}",  
    @"\*\*REF", 
    @"\*\*",
    @"/\*", 
    @"\*/",
    @"____",
    @"___",
    @"[", 
    @"]",
    @"(",
    @")",
    @":",
    @"-",
    @"/",
    @",",
    @";",
    @".",
    @"\\r\\n"
};

string regEx = "\\d";
foreach (string separator in separators) {
    regEx = string.Concat(regEx, "|", separator);
}

string value = "0: standby";
string[] symbols =  Regex.Split(value, regEx);

string[] separators = new string[] {
    @"} SPACEFILL DP",
    @"} ZEROFILL DP",
    @":",
    @"'\%s'", 
    @"\%s'", 
    @"<<<<", 
    @"<<<", 
    @"<<", 
    @"<",
    @">>>>", 
    @">>>",
    @">>",
    @">",
    @"system\\User", 
    @"{S_NomeRicetta}",  
    @"\*\*REF", 
    @"\*\*",
    @"/\*", 
    @"\*/",
    @"____",
    @"___",
    @"[", 
    @"]",
    @"(",
    @")",
    @":",
    @"-",
    @"/",
    @",",
    @";",
    @".",
    @"\\r\\n"
};

string regEx = "\\d";
foreach (string separator in separators) {
    regEx = string.Concat(regEx, "|", separator);
}

string value = "0: standby";
string[] symbols =  Regex.Split(value, regEx);

The result I expect is an array containing the string " standby" and probably some empty string too (e.g. between 0 and :). Instead, what I got is the following array:

[0]    ""    string
[1]    ""    string
[2]    ""    string
[3]    ""    string
[4]    ""    string
[5]    ""    string
[6]    ""    string
[7]    ""    string
[8]    "S"    string
[9]    ""    string
[10]    "t"    string
[11]    ""    string
[12]    "a"    string
[13]    ""    string
[14]    "n"    string
[15]    ""    string
[16]    "d"    string
[17]    ""    string
[18]    "b"    string
[19]    ""    string
[20]    "y"    string
[21]    ""    string
[22]    ""    string

[0]    ""    string
[1]    ""    string
[2]    ""    string
[3]    ""    string
[4]    ""    string
[5]    ""    string
[6]    ""    string
[7]    ""    string
[8]    "S"    string
[9]    ""    string
[10]    "t"    string
[11]    ""    string
[12]    "a"    string
[13]    ""    string
[14]    "n"    string
[15]    ""    string
[16]    "d"    string
[17]    ""    string
[18]    "b"    string
[19]    ""    string
[20]    "y"    string
[21]    ""    string
[22]    ""    string

While I was testing for giving the example to you, I realized that probably there is something wrong with the regular expression

ero•3y ago

Very I'm not really sure if you're meaning to escape some stuff in your separators? Like what's system\\User? Or \*\*REF? \%s? What do you expect those to match?

alkasel#159OP•3y ago

For **REF, since asterisk is a regex keyword, I need to escape it in order to let regex know that I want to match exactly **REF

ero•3y ago

Asterisk is not a regex "keyword"

alkasel#159OP•3y ago

I thought it was from here

alkasel#159OP•3y ago

https://stackoverflow.com/questions/2801549/how-do-i-replace-an-actual-asterisk-character-in-a-regex-expression

Stack Overflow

How do I replace an actual asterisk character (*) in a Regex expres...

I have a statement: I have a string such as content = "* test " I want to search and replace it with so when I am done the string contains this: content = "() test (*)" My code is:

alkasel#159OP•3y ago

This one is on C# specifically

alkasel#159OP•3y ago

https://stackoverflow.com/questions/23488512/find-and-replace-asterisk-from-a-string-using-regex

Stack Overflow

Find and replace Asterisk (*) from a string using Regex

I have a string like this: Durham * versus Yorkshire and I have used a regex in C# to replace that asterisk in the string with some text, as: string aString = "Durham * versus Yorkshire"; string

ero•3y ago

You're absolutely right, I'm sorry. I fully blanked on that one somehow

MODiX•3y ago

Ero#1111

REPL Result: Success

string[] separators =
{
    @"\} SPACEFILL DP",
    @"\} ZEROFILL DP",
    @":",
    @"'%s'", 
    @"%s'", 
    @"<<<<", 
    @"<<<", 
    @"<<", 
    @"<",
    @">>>>", 
    @">>>",
    @">>",
    @">",
    @"system\\User", 
    @"{S_NomeRicetta}",  
    @"\*\*REF", 
    @"\*\*",
    @"/\*", 
    @"\*/",
    @"____",
    @"___",
    @"\[", 
    @"\]",
    @"\(",
    @"\)",
    @":",
    @"-",
    @"/",
    @",",
    @";",
    @"\.",
    @"\r\n"
};

string pattern = @"\d";
foreach (string separator in separators) {
    pattern += $"|{separator}";
}

string value = "0: standby";
string[] symbols =  Regex.Split(value, pattern);

symbols

string[] separators =
{
    @"\} SPACEFILL DP",
    @"\} ZEROFILL DP",
    @":",
    @"'%s'", 
    @"%s'", 
    @"<<<<", 
    @"<<<", 
    @"<<", 
    @"<",
    @">>>>", 
    @">>>",
    @">>",
    @">",
    @"system\\User", 
    @"{S_NomeRicetta}",  
    @"\*\*REF", 
    @"\*\*",
    @"/\*", 
    @"\*/",
    @"____",
    @"___",
    @"\[", 
    @"\]",
    @"\(",
    @"\)",
    @":",
    @"-",
    @"/",
    @",",
    @";",
    @"\.",
    @"\r\n"
};

string pattern = @"\d";
foreach (string separator in separators) {
    pattern += $"|{separator}";
}

string value = "0: standby";
string[] symbols =  Regex.Split(value, pattern);

symbols

Result: string[]

[
  "",
  "",
  " standby"
]

[
  "",
  "",
  " standby"
]

Compile: 491.413ms | Execution: 56.063ms | React with ❌ to remove this embed.

ero•3y ago

But there are also other things you need to escape Like the period, which if not escaped, matches everything Which is what's caused your main issue Other things like parens, brackets, and braves need to be escaped too

alkasel#159OP•3y ago

Ok, thanks. I was trying to understand what are all the characters I need to escape

alkasel#159OP•3y ago

I was able to succeed by using this list too https://learn.microsoft.com/en-us/dotnet/standard/base-types/character-escapes-in-regular-expressions

Character Escapes in .NET Regular Expressions

Learn about special characters and escaped characters in .NET regular expressions.

alkasel#159OP•3y ago

Thank you for your help

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✅ Split string on list of strings and on whathever number

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