I have a pack of number say :
d123sd
dds123
123ss
dd542334ssdf
fsd54345ff
the full data always string int string, I use this to split it each group
string1 = ^(.*?)\D+
int2 = (\d+)
string3 = ([a - zA - Z] *$)
but I always gets an error if data only int string (example 123ss), since it's variable string1 reads the first digit, can anybody tell me where did I go wrong?
To match 0 or more non-digit chars at the start of a string you need to define your string1 as
string1 = ^(\D*)
It will capture 0 or more non-digit (\D) chars at the start of the string (^).
The whole string pattern can look like
^(\D*)(\d+)(\D*)$
See the Regulex graph:
See also the regex demo.
Related
I am trying to replace a single occurrence of a character '1' in a String with a different character.
This same character can occur multiple times in the String which I am not interested in.
For example, in the below string I want to replace the single occurrence of 1 with 2.
input:-0001011101
output:-0002011102
I tried the below regex but it is giving be wrong results
regex b1("(1){1}");
S1=regex_replace( S,
b1, "2");
Any help would be greatly appreciated.
If you used boost::regex, Boost regex library, you could simply use a lookaround-based solution like
(?<!1)1(?!1)
And then replace with 2.
With std::regex, you cannot use lookbehinds, but you can use a regex that captures either start of string or any one char other than your char, then matches your char, and then makes sure your char does not occur immediately on the right.
Then, you may replace with $01 backreference to Group 1 (the 0 is necessary since the $12 replacement pattern would be parsed as Group 12, an empty string here since there is no Group 12 in the match structure):
regex reg("([^1]|^)1(?!1)");
S1=std::regex_replace(S, regex, "$012");
See the C++ demo online:
#include <iostream>
#include <regex>
int main() {
std::string S = "-0001011101";
std::regex reg("([^1]|^)1(?!1)");
std::cout << std::regex_replace(S, reg, "$012") << std::endl;
return 0;
}
// => -0002011102
Details:
([^1]|^) - Capturing group 1: any char other than 1 ([^...] is a negated character class) or start of string (^ is a start of string anchor)
1 - a 1 char
(?!1) - a negative lookahead that fails the match if there is a 1 char immediately to the right of the current location.
Use a negative lookahead in the regexp to match a 1 that isn't followed by another 1:
regex b1("1(?!1)");
I need to format the price string in dart.
String can be: ₹ 2,19,990.00
String can be: $1,114.99
String can be: $14.99
What I tried:
void main() {
String str = "₹ 2,19,990.00";
RegExp regexp = RegExp("(\\d+[,.]?[\\d]*)");
RegExpMatch? match = regexp.firstMatch(str);
str = match!.group(1)!;
print(str);
}
What my output is: 2,19
What my output is: 1,114
What my output is: 14.99
Expected output: 219990.00
Expected output: 1114.99
Expected output: 14.99 (This one is correct because there is no comma)
The simplest solution would be to replace all non-digit/non-dot characters with nothing.
The most efficient way to do that is:
final re = RegExp(r"[^\d.]+");
String sanitizeCurrency(String input) => input.replaceAll(re, "");
You can't do it by matching because a match is always contiguous in the source string, and you want to omit the embedded ,s.
You can use this regex for search:
^\D+|(?<=\d),(?=\d)
And replace with an empty string i.e. "".
RegEx Details:
^: Start
\D+: Match 1+ non-digit characters
|: OR
(?<=\d),(?=\d): Match a comma if it surrounded with digits on both sides
RegEx Demo
Code: Using replaceAll method:
str = str.replaceAll(RegExp(r'^\D+|(?<=\d),(?=\d)'), '');
I have a string, myFile, that looks like: Name_2019-11-29_D_HPSeries.txt. I need to extract the letter D between the underscores...the letter could be any uppercase letter. Right now I am using a 2 step Regex code.
Dim bC As String = Regex.Match(myFile, "_[A-Z]+_").ToString
boatClass = Regex.Match(bC, "[A-Z]+").ToString
This works but I believe it could be done with one line. I tried the code below but it doesn't work.
boatClass = Regex.Replace(myFile, "_[A-Z]_", "[A-Z]").ToString
You can use positive lookarounds to avoid a 2-step process, checking that the characters before and after the letter are underscores without capturing them:
Dim myFile AS String = "Name_2019-11-29_D_HPSeries.txt"
Dim bC As String = Regex.Match(myFile, "(?<=_)[A-Z](?=_)").ToString
Console.WriteLine(bc)
Output:
D
You were almost there with a single char A-Z, but you could wrap it in a capturing group and then use the Match.Groups property.
_([A-Z])_
Regex demo | VB.Net Demo
For example
Dim myFile AS String = "Name_2019-11-29_D_HPSeries.txt"
Dim bC As String = Regex.Match(myFile, "_([A-Z])_").Groups(1).Value
Console.WriteLine(bc)
Result
D
VB.NET separate strings using regex split?
Im having a logical error with the pattern string variable, the error occur after i extend the string from "(-)" to "(-)(+)(/)(*)"..
Dim input As String = txtInput.Text
Dim pattern As String = "(-)(+)(/)(*)"
Dim substrings() As String = Regex.Split(input, pattern)
For Each match As String In substrings
lstOutput.Items.Add(match)
This is my output when my pattern string variable is "-" it works fine
input: dog-
output: dog
-
My desired output(This is want i want to happen) but there is something wrong with the code.. its having an error after i did this "(-)(+)(/)()" even this
"(-)" + "(+)" + "(/)" + "()"
input: dog+cat/tree
output: dog
+
cat
/
tree
when space character input from textbox to listbox
input: dog+cat/ tree
output: dog
+
cat
/
tree
You need a character class, not the sequence of subpatterns inside separate capturing gorups:
Dim pattern As String = "([+/*-])"
This pattern will match and capture into Group 1 (and thus, all the captured values will be part of the resulting array) a char that is either a +, /, * or -. Note the position of the hyphen: since it is the last char in the character class, it is treated as a literal -, not a range operator.
See the regex demo:
How to remove whitespace characters from the input string? I am using the following code that
Dim input As String = txtInput.Text
Dim symbol As String = "([-+*/])"
Dim substrings() As String = Regex.Split(input, symbol)
Dim cleaned As String = Regex.Replace(input, "\s", " ")
For Each match As String In substrings
lstOutput.Items.Add(match)
Next
Input: z + x
Output: z, + and x.
I want to get rid of the whitespace in the last item.
You may remove the redundant whitespace while splitting with
\s*([-+*/])\s*
See the regex demo. Also, it is a good idea to trim the input before passing to the regex replace method with .Trim().
Pattern details:
\s* - matches 0+ whitespaces (these will be discarded from the result as they are not captured)
([-+*/]) - Group 1 (captured texts will be output to the resulting array) capturing 1 char: -, +, * or /
\s* - matches 0+ whitespaces (these will be discarded from the result as they are not captured)