Develop Reference

C#: Increment only the last number of a String

I have strings that look like this:
1.23.4.34
12.4.67
127.3.2.21.3
1.1.1.9
This is supposed to be a collection of numbers, separated by '.' symbols, similar to an ip address. I need to increment only the last digit/digits.
Expected Output:
1.23.4.35
12.4.68
127.3.2.21.4
1.1.1.10
Basically, increment whatever the number that is after the last '.' symbol.
I tried this:
char last = numberString[numberString.Length - 1];
int number = Convert.ToInt32(last);
number = number + 1;
If I go with the above code, I just need to replace the characters after the last '.' symbol with the new number. How do I get this done, good folks? :)

It seems to me that one method would be to:
split the string on . to get an array of components.
turn the final component into an integer.
increment that integer.
turn it back into a string.
recombine the components with . characters.
See, for example, the following program:
using System;
namespace ConsoleApplication1 {
class Program {
static void Main(string[] args) {
String original = "1.23.4.34";
String[] components = original.Split('.');
int value = Int32.Parse(components[components.Length - 1]) + 1;
components[components.Length - 1] = value.ToString();
String newstring = String.Join(".",components);
Console.WriteLine(newstring);
}
}
}
which outputs the "next highest" value of:
1.23.4.35

You can use string.LastIndexOf().
string input = "127.3.2.21.4";
int lastIndex = input.LastIndexOf('.');
string lastNumber = input.Substring(lastIndex + 1);
string increment = (int.Parse(lastNumber) + 1).ToString();
string result = string.Concat(input.Substring(0, lastIndex + 1), increment);

You need to extract more than just the last character. What if the last character is a 9 and then you add 1 to it? Then you need to correctly add one to the preceding character as well. For example, the string 5.29 should be processed to become 5.30 and not simply 5.210 or 5.20.
So I suggest you split the string into its number sections. Parse the last section into an integer. Increment it and then create the string again. I leave it as an exercise for the poster to actually write the few lines of code. Good practice!

Something like this:
var ip = "1.23.4.34";
var last = int.Parse(ip.Split(".".ToCharArray(),
StringSplitOptions.RemoveEmptyEntries).Last());
last = last + 1;
ip = string.Format("{0}.{1}",ip.Remove(ip.LastIndexOf(".")) , last);
If you are dealing with IP, there will be some extra code in case of .034, which should be 035 instead of 35. But that logic is not that complicated.

It's simple as this, use Split() and Join() String methods
String test = "1.23.4.34"; // test string
String[] splits = test.Split('.'); // split by .
splits[splits.Length - 1] = (int.Parse(splits[splits.Length - 1])+1).ToString(); // Increment last integer (Note : Assume all are integers)
String answ = String.Join(".",splits); // Use string join to make the string from string array. uses . separator
Console.WriteLine(answ); // Answer : 1.23.4.35

Using a bit of Linq
int[] int_arr = numberString.Split('.').Select(num => Convert.ToInt32(num)).ToArray();
int_arr[int_arr.Length - 1]++;
numberString = "";
for(int i = 0; i < int_arr.Length; i++) {
if( i == int_arr.Length - 1) {
numberString += int_arr[i].ToString();
}
else {
numberString += (int_arr[i].ToString() + ".");
}
}
Note: on phone so can't test.

My Solution is:
private static string calcNextCode(string value, int index)
{
if (value is null) return "1";
if (value.Length == index + 1) return value + "1";
int lastNum;
int myIndex = value.Length - ++index;
char myValue = value[myIndex];
if (int.TryParse(myValue.ToString(), NumberStyles.Integer, null, out lastNum))
{
var aStringBuilder = new StringBuilder(value);
if (lastNum == 9)
{
lastNum = 0;
aStringBuilder.Remove(myIndex, 1);
aStringBuilder.Insert(myIndex, lastNum);
return calcNextCode(aStringBuilder.ToString(), index++);
}
else
{
lastNum++;
}
aStringBuilder.Remove(myIndex, 1);
aStringBuilder.Insert(myIndex, lastNum);
return aStringBuilder.ToString();
}
return calcNextCode(value, index++);
}

C# split comma separated values

How can I split comma separated strings with quoted strings that can also contain commas?
Example input:
John, Doe, "Sid, Nency", Smith
Expected output:
John
Doe
Sid, Nency
Smith
Split by commas was ok, but I've got requirement that strings like "Sid, Nency" are allowed. I tried to use regexes to split such values. Regex ",(?=([^\"]*\"[^\"]*\")*[^\"]*$)" is from Java question and it is not working good for my .NET code. It doubles some strings, finds extra results etc.
So what is the best way to split such strings?

It's because of the capture group. Just turn it into a non-capture group:
",(?=(?:[^""]*""[^""]*"")*[^""]*$)"
^^
The capture group is including the captured part in your results.
ideone demo
var regexObj = new Regex(#",(?=(?:[^""]*""[^""]*"")*[^""]*$)");
regexObj.Split(input).Select(s => s.Trim('\"', ' ')).ForEach(Console.WriteLine);
And just trim the results.

Just go through your string. As you go through your string keep track
if you're in a "block" or not. If you're - don't treat the comma as
a comma (as a separator). Otherwise do treat it as such. It's a simple
algorithm, I would write it myself. When you encounter first " you enter
a block. When you encounter next ", you end that block you were, and so on.
So you can do it with one pass through your string.
import java.util.ArrayList;
public class Test003 {
public static void main(String[] args) {
String s = " John, , , , \" Barry, John \" , , , , , Doe, \"Sid , Nency\", Smith ";
StringBuilder term = new StringBuilder();
boolean inQuote = false;
boolean inTerm = false;
ArrayList<String> terms = new ArrayList<String>();
for (int i=0; i<s.length(); i++){
char ch = s.charAt(i);
if (ch == ' '){
if (inQuote){
if (!inTerm) {
inTerm = true;
}
term.append(ch);
}
else {
if (inTerm){
terms.add(term.toString());
term.setLength(0);
inTerm = false;
}
}
}else if (ch== '"'){
term.append(ch); // comment this out if you don't need it
if (!inTerm){
inTerm = true;
}
inQuote = !inQuote;
}else if (ch == ','){
if (inQuote){
if (!inTerm){
inTerm = true;
}
term.append(ch);
}else{
if (inTerm){
terms.add(term.toString());
term.setLength(0);
inTerm = false;
}
}
}else{
if (!inTerm){
inTerm = true;
}
term.append(ch);
}
}
if (inTerm){
terms.add(term.toString());
}
for (String t : terms){
System.out.println("|" + t + "|");
}
}
}

I use the following code within my Csv Parser class to achieve this:
private string[] ParseLine(string line)
{
List<string> results = new List<string>();
bool inQuotes = false;
int index = 0;
StringBuilder currentValue = new StringBuilder(line.Length);
while (index < line.Length)
{
char c = line[index];
switch (c)
{
case '\"':
{
inQuotes = !inQuotes;
break;
}
default:
{
if (c == ',' && !inQuotes)
{
results.Add(currentValue.ToString());
currentValue.Clear();
}
else
currentValue.Append(c);
break;
}
}
++index;
}
results.Add(currentValue.ToString());
return results.ToArray();
} // eo ParseLine

If you find the regular expression too complex you can do it like this:
string initialString = "John, Doe, \"Sid, Nency\", Smith";
IEnumerable<string> splitted = initialString.Split('"');
splitted = splitted.SelectMany((str, index) => index % 2 == 0 ? str.Split(',') : new[] { str });
splitted = splitted.Where(str => !string.IsNullOrWhiteSpace(str)).Select(str => str.Trim());

Enabling partial name input to return values in c#

I have a c# web service that takes an String input and checks the input vs a text document full of Strings.
It works as follows, lets say I input "Australia" into the input, the service will return "Australia". However if I also input Aus (or aus, currently made it case insensitive) it should also return "Australia".
On the other hand if I input "tra", it shouldn't return Australia, only Strings that their first 3 indexes are "tra". (If it was Ch, it should return China, Chad... etc)
Currently my code looks like
public String countryCode(String input)
{
StringBuilder strings = new StringBuilder("", 10000);
String text = System.IO.File.ReadAllText(Server.MapPath("countryCodes.txt"));
String[] countries = Regex.Split(text, "#");
int v;
for (v = 0; v < countries.Length; v++)
{
if (countries[v].ToUpper().Contains(input) || countries[v].ToLower().Contains(input))
{
bool c = countries[v].ToUpper().Contains(input);
bool b = countries[v].ToLower().Contains(input);
if (b == true || c == true)
{
strings.Append(countries[v] + " ");
}
else
{
strings.Append("Country not found");
break;
}
}
}
String str = strings.ToString();
return str;
}
This is a start, but I am really having trouble comparing the indexes of strings.
My question is how can I construct something to check countries[v][0] vs input[0], if its the same, then check [1] and [1], and so on, until they aren't the same or input.Length is exceeded then return values appropriate?
Comment for clarifications if needed
Regards

I think your loop can be reduced to:
var valids = new List<String>();
foreach(String c in countries)
if(c.ToUpper().StartsWith(input.ToUpper()))
valids.Add(c);
return (valids.Any()) ? String.Join(",",valids) : "No Matches";
or LINQ:
var valids = countries.Select(c => c.ToUpper().StartsWith(input.ToUpper())).ToList();
return (valids.Any()) ? String.Join(",",valids) : "No Matches";

How can I search through a string in C# and replace areas bounded by a pattern?

We tried a few solutions now that try and use XML parsers. All fail because the strings are not always 100% valid XML. Here's our problem.
We have strings that look like this:
var a = "this is a testxxx of my data yxxx and of these xxx parts yxxx";
var b = "hello testxxx world yxxx ";
"this is a testxxx3yxxx and of these xxx1yxxx";
"hello testxxx1yxxx ";
The key here is that we want to do something to the data between xxx and yxxx. In the example above I would need a function that counts words and replaces the strings with a word count.
Is there a way we can process the string a and apply a function to change the data that's between the xxx and yxxx? Any function right now as we're just trying to get an idea of how to code this.

You can use Split method:
var parts = a.Split(new[] {"xxx", "yxxx"}, StringSplitOptions.None)
.Select((s, index) =>
{
string s1 = index%2 == 1 ? string.Format("{0}{2}{1}", "xxx", "yxxx", s + "1") : s;
return s1;
});
var result = string.Join("", parts);

If it always going to xxx and yxxx, you can use regex as suggested.
var stringBuilder = new StringBuilder();
Regex regex = new Regex("xxx(.*?)yxxx");
var splitGroups = Regex.Match(a);
foreach(var group in splitGroups)
{
var value = splitGroupsCopy[i];
// do something to value and then append it to string builder
stringBuilder.Append(string.Format("{0}{1}{2}", "xxx", value, "yxxx"));
}
I suppose this is as basic as it gets.

Using Regex.Replace will replace all the matches with your choice of text, something like this:
Regex rgx = new Regex("xxx.+yxxx");
string cleaned = rgx.Replace(a, "replacementtext");

This code will process each of the parts delimited by "xxx". It preserves the "xxx" separators. If you do not want to preserve the "xxx" separators, remove the two lines that say "result.Append(separator);".
Given:
"this is a testxxx of my data yxxx and there are many of these xxx parts yxxx"
It prints:
"this is a testxxx>> of my data y<<xxx and there are many of these xxx>> parts y<<xxx"
I'm assuming that's the kind of thing you want. Add your own processing to "processPart()".
using System;
using System.Text;
namespace ConsoleApplication1
{
internal class Program
{
private static void Main(string[] args)
{
string text = "this is a testxxx of my data yxxx and there are many of these xxx parts yxxx";
string separator = "xxx";
var result = new StringBuilder();
int index = 0;
while (true)
{
int start = text.IndexOf(separator, index);
if (start < 0)
{
result.Append(text.Substring(index));
break;
}
result.Append(text.Substring(index, start - index));
int end = text.IndexOf(separator, start + separator.Length);
if (end < 0)
{
throw new InvalidOperationException("Unbalanced separators.");
}
start += separator.Length;
result.Append(separator);
result.Append(processPart(text.Substring(start, end-start)));
result.Append(separator);
index = end + separator.Length;
}
Console.WriteLine(result);
}
private static string processPart(string part)
{
return ">>" + part + "<<";
}
}
}
[EDIT] Here's the code amended to work with two different separators:
using System;
using System.Text;
namespace ConsoleApplication1
{
internal class Program
{
private static void Main(string[] args)
{
string text = "this is a test<pre> of my data y</pre> and there are many of these <pre> parts y</pre>";
string separator1 = "<pre>";
string separator2 = "</pre>";
var result = new StringBuilder();
int index = 0;
while (true)
{
int start = text.IndexOf(separator1, index);
if (start < 0)
{
result.Append(text.Substring(index));
break;
}
result.Append(text.Substring(index, start - index));
int end = text.IndexOf(separator2, start + separator1.Length);
if (end < 0)
{
throw new InvalidOperationException("Unbalanced separators.");
}
start += separator1.Length;
result.Append(separator1);
result.Append(processPart(text.Substring(start, end-start)));
result.Append(separator2);
index = end + separator2.Length;
}
Console.WriteLine(result);
}
private static string processPart(string part)
{
return "|" + part + "|";
}
}
}

The indexOf() function will return to you the index of the first occurrence of a given substring.
(My indices might be a bit off, but) I would suggest doing something like this:
var searchme = "this is a testxxx of my data yxxx and there are many of these xxx parts yxxx";
var startindex= searchme.indexOf("xxx");
var endindex = searchme.indexOf("yxxx") + 3; //added 3 to find the index of the last 'x' instead of the index of the 'y' character
var stringpiece = searchme.substring(startindex, endindex - startindex);
and you can repeat that while startindex != -1
Like I said, the indices might be slightly off, you might have to add a +1 or -1 somewhere, but this will get you along nicely (I think).
Here is a little sample program that counts chars instead of words. But you should just need to change the processor function.
var a = "this is a testxxx of my data yxxx and there are many of these xxx parts yxxx";
a = ProcessString(a, CountChars);
string CountChars(string a)
{
return a.Length.ToString();
}
string ProcessString(string a, Func<string, string> processor)
{
int idx_start, idx_end = -4;
while ((idx_start = a.IndexOf("xxx", idx_end + 4)) >= 0)
{
idx_end = a.IndexOf("yxxx", idx_start + 3);
if (idx_end < 0)
break;
var string_in_between = a.Substring(idx_start + 3, idx_end - idx_start - 3);
var newString = processor(string_in_between);
a = a.Substring(0, idx_start + 3) + newString + a.Substring(idx_end, a.Length - idx_end);
idx_end -= string_in_between.Length - newString.Length;
}
return a;
}

I would use Regex Groups:
Here my solution to get the parts in the string:
private static IEnumerable<string> GetParts( string searchFor, string begin, string end ) {
string exp = string.Format("({0}(?<searchedPart>.+?){1})+", begin, end);
Regex regex = new Regex(exp);
MatchCollection matchCollection = regex.Matches(searchFor);
foreach (Match match in matchCollection) {
Group #group = match.Groups["searchedPart"];
yield return #group.ToString();
}
}
you can use it like to get the parts:
string a = "this is a testxxx of my data yxxx and there are many of these xxx parts yxxx";
IEnumerable<string> parts = GetParts(a, "xxx", "yxxx");
To replace the parts in the original String you can use the Regex Group to determine Length and StartPosition (#group.Index, #group.Length).

c# if String Contains 2 "hallo" [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
How would you count occurences of a string within a string (C#)?
I want to check if a String contains 2 things..
String hello = "hellohelloaklsdhas";
if hello.Contains(*hello 2 Times*); -> True
How can I solve this?

You could use a regex :)
return Regex.Matches(hello, "hello").Count == 2;
This matches the string hello for the pattern "hello" and returns true if the count is 2.

Regular expressions.
if (Regex.IsMatch(hello,#"(.*hello.*){2,}"))
I guess you meant "hello", and this will match a string with at least 2 "hello" (not exactly 2 "hello")

public static class StringExtensions
{
public static int Matches(this string text, string pattern)
{
int count = 0, i = 0;
while ((i = text.IndexOf(pattern, i)) != -1)
{
i += pattern.Length;
count++;
}
return count;
}
}
class Program
{
static void Main()
{
string s1 = "Sam's first name is Sam.";
string s2 = "Dot Net Perls is about Dot Net";
string s3 = "No duplicates here";
string s4 = "aaaa";
Console.WriteLine(s1.Matches("Sam")); // 2
Console.WriteLine(s1.Matches("cool")); // 0
Console.WriteLine(s2.Matches("Dot")); // 2
Console.WriteLine(s2.Matches("Net")); // 2
Console.WriteLine(s3.Matches("here")); // 1
Console.WriteLine(s3.Matches(" ")); // 2
Console.WriteLine(s4.Matches("aa")); // 2
}
}

You can use a regex, and check the length of the result of Matches function. If it's two you win.

new Regex("hello.*hello").IsMatch(hello)
or
Regex.IsMatch(hello, "hello.*hello")

If you use a regular expression MatchCollection you can get this easily:
MatchCollection matches;
Regex reg = new Regex("hello");
matches = reg.Matches("hellohelloaklsdhas");
return (matches.Count == 2);

IndexOf
You can use the IndexOf method to get the index of a certain string. This method has an overload that accepts a starting point, from where to look. When the specified string is not found, -1 is returned.
Here is an example that should speak for itself.
var theString = "hello hello bye hello";
int index = -1;
int helloCount = 0;
while((index = theString.IndexOf("hello", index+1)) != -1)
{
helloCount++;
}
return helloCount==2;
Regex
Another way to get the count is to use Regex:
return (Regex.Matches(hello, "hello").Count == 2);

IndexOf:
int FirstIndex = str.IndexOf("hello");
int SecondIndex = str.IndexOf("hello", FirstIndex + 1);
if(FirstIndex != -1 && SecondIndex != -1)
{
//contains 2 or more hello
}
else
{
//contains not
}
or if you want exactly 2: if(FirstIndex != -1 && SecondIndex != -1 && str.IndexOf("hello", SecondIndex) == -1)