I think I am too dumb to solve this problem...
I have some formulas which need to be "translated" from one syntax to another.
Let's say I have a formula that goes like that (it's a simple one, others have many "Ceilings" in it):
string formulaString = "If([Param1] = 0, 1, Ceiling([Param2] / 0.55) * [Param3])";
I need to replace "Ceiling()" with "Ceiling(; 1)" (basically, insert "; 1" before the ")").
My attempt is to split the fomulaString at "Ceiling(" so I am able to iterate through the string array and insert my string at the correct index (counting every "(" and ")" to get the right index)
What I have so far:
//splits correct, but loses "CEILING("
string[] parts = formulaString.Split(new[] { "CEILING(" }, StringSplitOptions.None);
//splits almost correct, "CEILING(" is in another group
string[] parts = Regex.Split(formulaString, #"(CEILING\()");
//splits almost every letter
string[] parts = Regex.Split(formulaString, #"(?=[(CEILING\()])");
When everything is done, I concat the string so I have my complete formula again.
What do I have to set as Regex pattern to achieve this sample? (Or any other method that will help me)
part1 = "If([Param1] = 0, 1, ";
part2 = "Ceiling([Param2] / 0.55) * [Param3])";
//part3 = next "CEILING(" in a longer formula and so on...
As I mention in a comment, you almost got it: (?=Ceiling). This is incomplete for your use case unfortunately.
I need to replace "Ceiling()" with "Ceiling(; 1)" (basically, insert "; 1" before the ")").
Depending on your regex engine (for example JS) this works:
string[] parts = Regex.Split(formulaString, #"(?<=Ceiling\([^)]*(?=\)))");
string modifiedFormula = String.join("; 1", parts);
The regex
(?<=Ceiling\([^)]*(?=\)))
(?<= ) Positive lookbehind
Ceiling\( Search for literal "Ceiling("
[^)] Match any char which is not ")" ..
* .. 0 or more times
(?=\)) Positive lookahead for ")", effectively making us stop before the ")"
This regex is a zero-assertion, therefore nothing is lost and it will cut your strings before the last ")" in every "Ceiling()".
This solution would break whenever you have nested "Ceiling()". Then your only solution would be writing your own parser for the same reasons why you can't parse markup with regex.
Regex.Replace(formulaString, #"(?<=Ceiling\()(.*?)(?=\))","$1; 1");
Note: This will not work for nested "Ceilings", but it does for Ceiling(), It will also not work fir Ceiling(AnotherFunc(x)). For that you need something like:
Regex.Replace(formulaString, #"(?<=Ceiling\()((.*\((?>[^()]+|(?1))*\))*|[^\)]*)(\))","$1; 1$3");
but I could not get that to work with .NET, only in JavaScript.
This is my solution:
private string ConvertCeiling(string formula)
{
int ceilingsCount = formula.CountOccurences("Ceiling(");
int startIndex = 0;
int bracketCounter;
for (int i = 0; i < ceilingsCount; i++)
{
startIndex = formula.IndexOf("Ceiling(", startIndex);
bracketCounter = 0;
for (int j = 0; j < formula.Length; j++)
{
if (j < startIndex) continue;
var c = formula[j];
if (c == '(')
{
bracketCounter++;
}
if (c == ')')
{
bracketCounter--;
if (bracketCounter == 0)
{
// found end
formula = formula.Insert(j, "; 1");
startIndex++;
break;
}
}
}
}
return formula;
}
And CountOccurence:
public static int CountOccurences(this string value, string parameter)
{
int counter = 0;
int startIndex = 0;
int indexOfCeiling;
do
{
indexOfCeiling = value.IndexOf(parameter, startIndex);
if (indexOfCeiling < 0)
{
break;
}
else
{
startIndex = indexOfCeiling + 1;
counter++;
}
} while (true);
return counter;
}
I am trying to print a string by thermal printer, but the problem is that paper accept only 32 charcters in a line and than break rest text to another line, by this last character always cut into two parts and string is hard to understand.
Example:
string PrintStr = "01-(200),02-(200),03-(200),04-(200),05-(200)";
Current output:
01-(200),02-(200),03-(200),04-(20 # <- 200 is broken into 20 and 0
0),05-(200)
Better output:
01-(200),02-(200),03-(200), # Split on comma, numbers are preserved
04-(200),05-(200)
I also use a Linq mehtod to break line after 32th character but the last character is cutting. I just want after last Comma "," in first 32 characters a new line will be add by that my string will break in readable text. I am sharing my code. Thanks in advance for help..
Input:
var PrintStr = "01-(200),02-(200),03-(200),04-(200),05-(200),06-(200),07-(200),08-(200),09-
(200),10-(200),11-(200),12-(200),13-(200),14-(200),15-
(200),16-(200),17-(200),18-(200),19-(200),20-(200),21-(200),22-(200),23-(200),24-(200),25-(200),26-
(200),27-(200),28-(200),29-(200),30-(200),31-(
200),32-(200),33-(200),34-(200),35-(200),36-(200),37-(200),38-(200),39-(200),40-(200),41-(200),42-
(200),43-(200),44-(200),45-(200),46-(200),47-(200),48-
(200),49-(200),50-(200),51-(200),52-(200),53-(200),54-(200),55-(200),56-(200),57-(200),58-(200),59-
(200),60-(200),61-(200),62-(200),63-(200),64-
(200),65-(200),66-(200),67-(200),A1111-(200)"
Code (my attept):
var AdjustPrintStr = string.Join(Environment.NewLine, PrintStr
.ToLookup(c => k++ / 32)
.Select(e => new String(e.ToArray())));
Output (current, unwanted):
01-(200),02-(200
),03-(200),04-(200),05-(200),06-
(200),07-(200),08-(200),09-(200)
,10-(200),11-(200),12-(200),13-(
200),14-(200),15-(200),16-(200),
17-(200),18-(200),19-(200),20-(2
00),21-(200),22-(200),23-(200),2
4-(200),25-(200),26-(200),27-(20
0),28-(200),29-(200),30-(200),31
-(200),32-(200),33-(200),34-(200
),35-(200),36-(200),37-(200),38-
(200),39-(200),40-(200),41-(200)
,42-(200),43-(200),44-(200),45-(
200),46-(200),47-(200),48-(200),
49-(200),50-(200),51-(200),52-(2
00),53-(200),54-(200),55-(200),5
6-(200),57-(200),58-(200),59-(20
0),60-(200),61-(200),62-(200),63
-(200),64-(200),65-(200),66-(200
Note, that the last "),A1111-(200)" fragment is lost
Well, you have to implement such a routine
(split text at at characters ensuring at most maxWidth characters in each line) manually;
it's not that difficult:
public static IEnumerable<string> MySplit(string text,
int maxWidth, params char[] at) {
if (null == text)
throw new ArgumentNullException(nameof(text));
else if (maxWidth <= 0)
throw new ArgumentOutOfRangeException(nameof(maxWidth));
else if (null == at)
throw new ArgumentNullException(nameof(at));
int startIndex = 0;
int bestIndex = -1;
for (int i = 0; i < text.Length; ++ i) {
if ((i - startIndex) > maxWidth) {
if (bestIndex < 0)
bestIndex = i - 1;
yield return text.Substring(startIndex, bestIndex - startIndex + 1);
startIndex = bestIndex += 1;
bestIndex = -1;
}
if (at.Contains(text[i]))
bestIndex = i;
}
yield return text.Substring(startIndex);
}
Now, let's print out the source string:
string PrintStr = #"01-(200),02-(200),03-(200),04-(200),05-(200),06-(200),07-(200),08-(200),09-
(200),10-(200),11-(200),12-(200),13-(200),14-(200),15-
(200),16-(200),17-(200),18-(200),19-(200),20-(200),21-(200),22-(200),23-(200),24-(200),25-(200),26-
(200),27-(200),28-(200),29-(200),30-(200),31-(
200),32-(200),33-(200),34-(200),35-(200),36-(200),37-(200),38-(200),39-(200),40-(200),41-(200),42-
(200),43-(200),44-(200),45-(200),46-(200),47-(200),48-
(200),49-(200),50-(200),51-(200),52-(200),53-(200),54-(200),55-(200),56-(200),57-(200),58-(200),59-
(200),60-(200),61-(200),62-(200),63-(200),64-
(200),65-(200),66-(200),67-(200),A1111-(200)";
It seems, you should preprocess it in order to remove all new lines, tabulations, spaces etc. and
only then split it:
// Let's remove all white spaces (new lines, tabulations, spaces)
PrintStr = Regex.Replace(PrintStr, #"\s+", "");
// split on comma ',' while ensuring each lines <= 32 characters
var result = string.Join(Environment.NewLine, MySplit(PrintStr, 32, ','));
Console.Write(result);
Outcome:
01-(200),02-(200),03-(200),
04-(200),05-(200),06-(200),
07-(200),08-(200),09-(200),
10-(200),11-(200),12-(200),
13-(200),14-(200),15-(200),
16-(200),17-(200),18-(200),
19-(200),20-(200),21-(200),
22-(200),23-(200),24-(200),
25-(200),26-(200),27-(200),
28-(200),29-(200),30-(200),
31-(200),32-(200),33-(200),
34-(200),35-(200),36-(200),
37-(200),38-(200),39-(200),
40-(200),41-(200),42-(200),
43-(200),44-(200),45-(200),
46-(200),47-(200),48-(200),
49-(200),50-(200),51-(200),
52-(200),53-(200),54-(200),
55-(200),56-(200),57-(200),
58-(200),59-(200),60-(200),
61-(200),62-(200),63-(200),
64-(200),65-(200),66-(200),
67-(200),A1111-(200)
Hope, it's the very picture you want to see after printing
I need to write different paragraphs of text within a certain area. For instance, I have drawn a box to the console that looks like this:
/----------------------\
| |
| |
| |
| |
\----------------------/
How would I write text within it, but wrap it to the next line if it gets too long?
Split on last space before your row length?
int myLimit = 10;
string sentence = "this is a long sentence that needs splitting to fit";
string[] words = sentence.Split(new char[] { ' ' });
IList<string> sentenceParts = new List<string>();
sentenceParts.Add(string.Empty);
int partCounter = 0;
foreach (string word in words)
{
if ((sentenceParts[partCounter] + word).Length > myLimit)
{
partCounter++;
sentenceParts.Add(string.Empty);
}
sentenceParts[partCounter] += word + " ";
}
foreach (string x in sentenceParts)
Console.WriteLine(x);
UPDATE (the solution above lost the last word in some cases):
int myLimit = 10;
string sentence = "this is a long sentence that needs splitting to fit";
string[] words = sentence.Split(' ');
StringBuilder newSentence = new StringBuilder();
string line = "";
foreach (string word in words)
{
if ((line + word).Length > myLimit)
{
newSentence.AppendLine(line);
line = "";
}
line += string.Format("{0} ", word);
}
if (line.Length > 0)
newSentence.AppendLine(line);
Console.WriteLine(newSentence.ToString());
Here's one that is lightly tested and uses LastIndexOf to speed things along (a guess):
private static string Wrap(string v, int size)
{
v = v.TrimStart();
if (v.Length <= size) return v;
var nextspace = v.LastIndexOf(' ', size);
if (-1 == nextspace) nextspace = Math.Min(v.Length, size);
return v.Substring(0, nextspace) + ((nextspace >= v.Length) ?
"" : "\n" + Wrap(v.Substring(nextspace), size));
}
I started with Jim H.'s solution and end up with this method. Only problem is if text has any word that longer than limit. But works well.
public static List<string> GetWordGroups(string text, int limit)
{
var words = text.Split(new string[] { " ", "\r\n", "\n" }, StringSplitOptions.None);
List<string> wordList = new List<string>();
string line = "";
foreach (string word in words)
{
if (!string.IsNullOrWhiteSpace(word))
{
var newLine = string.Join(" ", line, word).Trim();
if (newLine.Length >= limit)
{
wordList.Add(line);
line = word;
}
else
{
line = newLine;
}
}
}
if (line.Length > 0)
wordList.Add(line);
return wordList;
}
I modified the version of Jim H such that it supports some special cases.
For example the case when the sentence does not contain any whitespace character; I also noted that there is a problem when a line has a space at the last position; then the space is added at the end and you end up with one character too much.
Here is my version just in case someone is interested:
public static List<string> WordWrap(string input, int maxCharacters)
{
List<string> lines = new List<string>();
if (!input.Contains(" "))
{
int start = 0;
while (start < input.Length)
{
lines.Add(input.Substring(start, Math.Min(maxCharacters, input.Length - start)));
start += maxCharacters;
}
}
else
{
string[] words = input.Split(' ');
string line = "";
foreach (string word in words)
{
if ((line + word).Length > maxCharacters)
{
lines.Add(line.Trim());
line = "";
}
line += string.Format("{0} ", word);
}
if (line.Length > 0)
{
lines.Add(line.Trim());
}
}
return lines;
}
This is a more complete and tested solution.
The bool overflow parameter specifies, whether long words are chunked in addition to splitting up by spaces.
Consecutive whitespaces, as well as \r, \n, are ignored and collapsed into one space.
Edge cases are throughfully tested
public static string WrapText(string text, int width, bool overflow)
{
StringBuilder result = new StringBuilder();
int index = 0;
int column = 0;
while (index < text.Length)
{
int spaceIndex = text.IndexOfAny(new[] { ' ', '\t', '\r', '\n' }, index);
if (spaceIndex == -1)
{
break;
}
else if (spaceIndex == index)
{
index++;
}
else
{
AddWord(text.Substring(index, spaceIndex - index));
index = spaceIndex + 1;
}
}
if (index < text.Length) AddWord(text.Substring(index));
void AddWord(string word)
{
if (!overflow && word.Length > width)
{
int wordIndex = 0;
while (wordIndex < word.Length)
{
string subWord = word.Substring(wordIndex, Math.Min(width, word.Length - wordIndex));
AddWord(subWord);
wordIndex += subWord.Length;
}
}
else
{
if (column + word.Length >= width)
{
if (column > 0)
{
result.AppendLine();
column = 0;
}
}
else if (column > 0)
{
result.Append(" ");
column++;
}
result.Append(word);
column += word.Length;
}
}
return result.ToString();
}
I modified Manfred's version. If you put a string with the '\n' character in it, it will wrap the text strangely because it will count it as another character. With this minor change all will go smoothly.
public static List<string> WordWrap(string input, int maxCharacters)
{
List<string> lines = new List<string>();
if (!input.Contains(" ") && !input.Contains("\n"))
{
int start = 0;
while (start < input.Length)
{
lines.Add(input.Substring(start, Math.Min(maxCharacters, input.Length - start)));
start += maxCharacters;
}
}
else
{
string[] paragraphs = input.Split('\n');
foreach (string paragraph in paragraphs)
{
string[] words = paragraph.Split(' ');
string line = "";
foreach (string word in words)
{
if ((line + word).Length > maxCharacters)
{
lines.Add(line.Trim());
line = "";
}
line += string.Format("{0} ", word);
}
if (line.Length > 0)
{
lines.Add(line.Trim());
}
}
}
return lines;
}
Other answers didn't consider East Asian languages, which don't use space to break words.
In general, a sentence in East Asian languages can be wrapped in any position between characters, except certain punctuations (it is not a big problem even if ignore punctuation rules). It is much simpler than European languages but when consider mixing different languages, you have to detect the language of each character by checking the Unicode table, and then apply the break lines by space algorithm only for European languages parts.
References:
https://en.wikipedia.org/wiki/Line_wrap_and_word_wrap
https://en.wikipedia.org/wiki/Line_breaking_rules_in_East_Asian_languages
https://en.wikibooks.org/wiki/Unicode/Character_reference/0000-0FFF
This code will wrap the paragraph text. It will break the paragraph text into lines. If it encounters any word which is even larger than the line length, it will break the word into multiple lines too.
private const int max_line_length = 25;
private string wrapLinesToFormattedText(string p_actual_string) {
string formatted_string = "";
int available_length = max_line_length;
string[] word_arr = p_actual_string.Trim().Split(' ');
foreach (string w in word_arr) {
string word = w;
if (word == "") {
continue;
}
int word_length = word.Length;
//if the word is even longer than the length that the line can have
//the large word will get break down into lines following by the successive words
if (word_length >= max_line_length)
{
if (available_length > 0)
{
formatted_string += word.Substring(0, available_length) + "\n";
word = word.Substring(available_length);
}
else
{
formatted_string += "\n";
}
word = word + " ";
available_length = max_line_length;
for (var count = 0;count<word.Length;count++) {
char ch = word.ElementAt(count);
if (available_length==0) {
formatted_string += "\n";
available_length = max_line_length;
}
formatted_string += ch;
available_length--;
}
continue;
}
if ((word_length+1) <= available_length)
{
formatted_string += word+" ";
available_length -= (word_length+1);
continue;
}
else {
available_length = max_line_length;
formatted_string += "\n"+word+" " ;
available_length -= (word_length + 1);
continue;
}
}//end of foreach loop
return formatted_string;
}
//end of function wrapLinesToFormattedText
Blockquote
Here is a small piece of optimized code for wrapping text according to float sentence length limit written in Visual Basic9.
Dim stringString = "Great code! I wish I could found that when searching for Print Word Wrap VB.Net and other variations when searching on google. I’d never heard of MeasureString until you guys mentioned it. In my defense, I’m not a UI programmer either, so I don’t feel bad for not knowing"
Dim newstring = ""
Dim t As Integer = 1
Dim f As Integer = 0
Dim z As Integer = 0
Dim p As Integer = stringString.Length
Dim myArray As New ArrayList
Dim endOfText As Boolean = False REM to exit loop after finding the last words
Dim segmentLimit As Integer = 45
For t = z To p Step segmentLimit REM you can adjust this variable to fit your needs
newstring = String.Empty
newstring += Strings.Mid(stringString, 1, 45)
If Strings.Left(newstring, 1) = " " Then REM Chr(13) doesn't work, that's why I have put a physical space
newstring = Strings.Right(newstring, newstring.Length - 1)
End If
If stringString.Length < 45 Then
endOfText = True
newstring = stringString
myArray.Add(newstring) REM fills the last entry then exits
myArray.TrimToSize()
Exit For
Else
stringString = Strings.Right(stringString, stringString.Length - 45)
End If
z += 44 + f
If Not Strings.Right(newstring, 1) = Chr(32) Then REM to detect space
Do Until Strings.Right(newstring, z + 1) = " "
If Strings.Right(newstring, z + f) = " " OrElse Strings.Left(stringString, 1) = " " Then
Exit Do
End If
newstring += Strings.Left(stringString, 1)
stringString = Strings.Right(stringString, stringString.Length - 1) REM crops the original
p = stringString.Length REM string from left by 45 characters and additional characters
t += f
f += 1
Loop
myArray.Add(newstring) REM puts the resulting segments of text in an array
myArray.TrimToSize()
newstring = String.Empty REM empties the string to load the next 45 characters
End If
t = 1
f = 1
Next
For Each item In myArray
MsgBox(item)
'txtSegmentedText.Text &= vbCrLf & item
Next
I know I am a bit late, But I managed to get a solution going by using recursion.
I think its one of the cleanest solutions proposed here.
Recursive Function:
public StringBuilder TextArea { get; set; } = new StringBuilder();
public void GenerateMultiLineTextArea(string value, int length)
{
// first call - first length values -> append first length values, remove first length values from value, make second call
// second call - second length values -> append second length values, remove first length values from value, make third call
// third call - value length is less then length just append as it is
if (value.Length <= length && value.Length != 0)
{
TextArea.Append($"|{value.PadRight(length)}" + "|");
}
else
{
TextArea.Append($"|{value.Substring(0, length).ToString()}".PadLeft(length) + "|\r\n");
value = value.Substring(length, (value.Length) - (length));
GenerateMultiLineTextArea(value, length);
}
}
Usage:
string LongString =
"This is a really long string that needs to break after it reaches a certain limit. " +
"This is a really long string that needs to break after it reaches a certain limit." + "This is a really long string that needs to break after it reaches a certain limit.";
GenerateMultiLineTextArea(LongString, 22);
Console.WriteLine("/----------------------\\");
Console.WriteLine(TextArea.ToString());
Console.WriteLine("\\----------------------/");
Outputs:
/----------------------\
|This is a really long |
|string that needs to b|
|reak after it reaches |
|a certain limit. This |
|is a really long strin|
|g that needs to break |
|after it reaches a cer|
|tain limit.This is a r|
|eally long string that|
| needs to break after |
|it reaches a certain l|
|imit. |
\----------------------/
Not entirely sure this is possible, but say I have two strings like so:
"IAmAString-00001"
"IAmAString-00023"
What would be a quick'n'easy way to iterate from IAmAString-0001 to IAmAString-00023 by moving up the index of just the numbers on the end?
The problem is a bit more general than that, for example the string I could be dealing could be of any format but the last bunch of chars will always be numbers, so something like Super_Confusing-String#w00t0003 and in that case the last 0003 would be what I'd use to iterate through.
Any ideas?
You can use char.IsDigit:
static void Main(string[] args)
{
var s = "IAmAString-00001";
int index = -1;
for (int i = 0; i < s.Length; i++)
{
if (char.IsDigit(s[i]))
{
index = i;
break;
}
}
if (index == -1)
Console.WriteLine("digits not found");
else
Console.WriteLine("digits: {0}", s.Substring(index));
}
which produces this output:
digits: 00001
string.Format and a for loop should do what you want.
for(int i = 0; i <=23; i++)
{
string.Format("IAmAString-{0:D4}",i);
}
or something close to that (not sitting in front of a compiler).
string start = "IAmAString-00001";
string end = "IAmAString-00023";
// match constant part and ending digits
var matchstart = Regex.Match(start,#"^(.*?)(\d+)$");
int numberstart = int.Parse(matchstart.Groups[2].Value);
var matchend = Regex.Match(end,#"^(.*?)(\d+)$");
int numberend = int.Parse(matchend.Groups[2].Value);
// constant parts must be the same
if (matchstart.Groups[1].Value != matchend.Groups[1].Value)
throw new ArgumentException("");
// create a format string with same number of digits as original
string format = new string('0', matchstart.Groups[2].Length);
for (int ii = numberstart; ii <= numberend; ++ii)
Console.WriteLine(matchstart.Groups[1].Value + ii.ToString(format));
You could use a Regex:
var match=Regex.Match("Super_Confusing-String#w00t0003",#"(?<=(^.*\D)|^)\d+$");
if(match.Success)
{
var val=int.Parse(match.Value);
Console.WriteLine(val);
}
To answer more specifically, you could use named groups to extract what you need:
var match=Regex.Match(
"Super_Confusing-String#w00t0003",
#"(?<prefix>(^.*\D)|^)(?<digits>\d+)$");
if(match.Success)
{
var prefix=match.Groups["prefix"].Value;
Console.WriteLine(prefix);
var val=int.Parse(match.Groups["digits"].Value);
Console.WriteLine(val);
}
If you can assume that the last 5 characters are the number then:
string prefix = "myprefix-";
for (int i=1; i <=23; i++)
{
Console.WriteLine(myPrefix+i.ToString("D5"));
}
This function will find the trailing number.
private int FindTrailingNumber(string str)
{
string numString = "";
int numTest;
for (int i = str.Length - 1; i > 0; i--)
{
char c = str[i];
if (int.TryParse(c.ToString(), out numTest))
{
numString = c + numString;
}
}
return int.Parse(numString);
}
Assuming all your base strings are the same, this would iterate between strings.
string s1 = "asdf123";
string s2 = "asdf127";
int num1 = FindTrailingNumber(s1);
int num2 = FindTrailingNumber(s2);
string strBase = s1.Replace(num1.ToString(), "");
for (int i = num1; i <= num2; i++)
{
Console.WriteLine(strBase + i.ToString());
}
I think it would be better if you do the search from the last (Rick already upvoted you since it was ur logic :-))
static void Main(string[] args)
{
var s = "IAmAString-00001";
int index = -1;
for (int i = s.Length - 1; i >=0; i--)
{
if (!char.IsDigit(s[i]))
{
index = i;
break;
}
}
if (index == -1)
Console.WriteLine("digits not found");
else
Console.WriteLine("digits: {0}", s.Substring(index));
Console.ReadKey();
}
HTH
If the last X numbers are always digits, then:
int x = 5;
string s = "IAmAString-00001";
int num = int.Parse(s.Substring(s.Length - x, x));
Console.WriteLine("Your Number is: {0}", num);
If the last digits can be 3, 4, or 5 in length, then you will need a little more logic:
int x = 0;
string s = "IAmAString-00001";
foreach (char c in s.Reverse())//Use Reverse() so you start with digits only.
{
if(char.IsDigit(c) == false)
break;//If we start hitting non-digit characters, then exit the loop.
++x;
}
int num = int.Parse(s.Substring(s.Length - x, x));
Console.WriteLine("Your Number is: {0}", num);
I'm not good with complicated RegEx. Because of this, I always shy away from it when maximum optimization is unnecessary. The reason for this is RegEx doesn't always parse strings the way you expect it to. If there is and alternate solution that will still run fast then I'd rather go that route as it's easier for me to understand and know that it will work with any combination of strings.
For Example: if you use some of the other solutions presented here with a string like "I2AmAString-000001", then you will get "2000001" as your number instead of "1".