I have a requirement to find and extract a number contained within a string.
For example, from these strings:
string test = "1 test"
string test1 = " 1 test"
string test2 = "test 99"
How can I do this?
\d+ is the regex for an integer number. So
//System.Text.RegularExpressions.Regex
resultString = Regex.Match(subjectString, #"\d+").Value;
returns a string containing the first occurrence of a number in subjectString.
Int32.Parse(resultString) will then give you the number.
Here's how I cleanse phone numbers to get the digits only:
string numericPhone = new String(phone.Where(Char.IsDigit).ToArray());
go through the string and use Char.IsDigit
string a = "str123";
string b = string.Empty;
int val;
for (int i=0; i< a.Length; i++)
{
if (Char.IsDigit(a[i]))
b += a[i];
}
if (b.Length>0)
val = int.Parse(b);
use regular expression ...
Regex re = new Regex(#"\d+");
Match m = re.Match("test 66");
if (m.Success)
{
Console.WriteLine(string.Format("RegEx found " + m.Value + " at position " + m.Index.ToString()));
}
else
{
Console.WriteLine("You didn't enter a string containing a number!");
}
What I use to get Phone Numbers without any punctuation...
var phone = "(787) 763-6511";
string.Join("", phone.ToCharArray().Where(Char.IsDigit));
// result: 7877636511
Regex.Split can extract numbers from strings. You get all the numbers that are found in a string.
string input = "There are 4 numbers in this string: 40, 30, and 10.";
// Split on one or more non-digit characters.
string[] numbers = Regex.Split(input, #"\D+");
foreach (string value in numbers)
{
if (!string.IsNullOrEmpty(value))
{
int i = int.Parse(value);
Console.WriteLine("Number: {0}", i);
}
}
Output:
Number: 4
Number: 40
Number: 30
Number: 10
if the number has a decimal points, you can use below
using System;
using System.Text.RegularExpressions;
namespace Rextester
{
public class Program
{
public static void Main(string[] args)
{
//Your code goes here
Console.WriteLine(Regex.Match("anything 876.8 anything", #"\d+\.*\d*").Value);
Console.WriteLine(Regex.Match("anything 876 anything", #"\d+\.*\d*").Value);
Console.WriteLine(Regex.Match("$876435", #"\d+\.*\d*").Value);
Console.WriteLine(Regex.Match("$876.435", #"\d+\.*\d*").Value);
}
}
}
results :
"anything 876.8 anything" ==> 876.8
"anything 876 anything" ==> 876
"$876435" ==> 876435
"$876.435" ==> 876.435
Sample : https://dotnetfiddle.net/IrtqVt
Here's a Linq version:
string s = "123iuow45ss";
var getNumbers = (from t in s
where char.IsDigit(t)
select t).ToArray();
Console.WriteLine(new string(getNumbers));
Another simple solution using Regex
You should need to use this
using System.Text.RegularExpressions;
and the code is
string var = "Hello3453232wor705Ld";
string mystr = Regex.Replace(var, #"\d", "");
string mynumber = Regex.Replace(var, #"\D", "");
Console.WriteLine(mystr);
Console.WriteLine(mynumber);
You can also try this
string.Join(null,System.Text.RegularExpressions.Regex.Split(expr, "[^\\d]"));
Here is another Linq approach which extracts the first number out of a string.
string input = "123 foo 456";
int result = 0;
bool success = int.TryParse(new string(input
.SkipWhile(x => !char.IsDigit(x))
.TakeWhile(x => char.IsDigit(x))
.ToArray()), out result);
Examples:
string input = "123 foo 456"; // 123
string input = "foo 456"; // 456
string input = "123 foo"; // 123
Just use a RegEx to match the string, then convert:
Match match = Regex.Match(test , #"(\d+)");
if (match.Success) {
return int.Parse(match.Groups[1].Value);
}
string input = "Hello 20, I am 30 and he is 40";
var numbers = Regex.Matches(input, #"\d+").OfType<Match>().Select(m => int.Parse(m.Value)).ToArray();
You can do this using String property like below:
return new String(input.Where(Char.IsDigit).ToArray());
which gives only number from string.
For those who want decimal number from a string with Regex in TWO line:
decimal result = 0;
decimal.TryParse(Regex.Match(s, #"\d+").Value, out result);
Same thing applys to float, long, etc...
var match=Regex.Match(#"a99b",#"\d+");
if(match.Success)
{
int val;
if(int.TryParse(match.Value,out val))
{
//val is set
}
}
The question doesn't explicitly state that you just want the characters 0 to 9 but it wouldn't be a stretch to believe that is true from your example set and comments. So here is the code that does that.
string digitsOnly = String.Empty;
foreach (char c in s)
{
// Do not use IsDigit as it will include more than the characters 0 through to 9
if (c >= '0' && c <= '9') digitsOnly += c;
}
Why you don't want to use Char.IsDigit() - Numbers include characters such as fractions, subscripts, superscripts, Roman numerals, currency numerators, encircled numbers, and script-specific digits.
Here is another simple solution using Linq which extracts only the numeric values from a string.
var numbers = string.Concat(stringInput.Where(char.IsNumber));
Example:
var numbers = string.Concat("(787) 763-6511".Where(char.IsNumber));
Gives: "7877636511"
var outputString = String.Join("", inputString.Where(Char.IsDigit));
Get all numbers in the string.
So if you use for examaple '1 plus 2' it will get '12'.
Extension method to get all positive numbers contained in a string:
public static List<long> Numbers(this string str)
{
var nums = new List<long>();
var start = -1;
for (int i = 0; i < str.Length; i++)
{
if (start < 0 && Char.IsDigit(str[i]))
{
start = i;
}
else if (start >= 0 && !Char.IsDigit(str[i]))
{
nums.Add(long.Parse(str.Substring(start, i - start)));
start = -1;
}
}
if (start >= 0)
nums.Add(long.Parse(str.Substring(start, str.Length - start)));
return nums;
}
If you want negative numbers as well simply modify this code to handle the minus sign (-)
Given this input:
"I was born in 1989, 27 years ago from now (2016)"
The resulting numbers list will be:
[1989, 27, 2016]
An interesting approach is provided here by Ahmad Mageed, uses Regex and StringBuilder to extract the integers in the order in which they appear in the string.
An example using Regex.Split based on the post by Ahmad Mageed is as follows:
var dateText = "MARCH-14-Tue";
string splitPattern = #"[^\d]";
string[] result = Regex.Split(dateText, splitPattern);
var finalresult = string.Join("", result.Where(e => !String.IsNullOrEmpty(e)));
int DayDateInt = 0;
int.TryParse(finalresult, out DayDateInt);
I have used this one-liner to pull all numbers from any string.
var phoneNumber = "(555)123-4567";
var numsOnly = string.Join("", new Regex("[0-9]").Matches(phoneNumber)); // 5551234567
string verificationCode ="dmdsnjds5344gfgk65585";
string code = "";
Regex r1 = new Regex("\\d+");
Match m1 = r1.Match(verificationCode);
while (m1.Success)
{
code += m1.Value;
m1 = m1.NextMatch();
}
Did the reverse of one of the answers to this question:
How to remove numbers from string using Regex.Replace?
// Pull out only the numbers from the string using LINQ
var numbersFromString = new String(input.Where(x => x >= '0' && x <= '9').ToArray());
var numericVal = Int32.Parse(numbersFromString);
Here is my Algorithm
//Fast, C Language friendly
public static int GetNumber(string Text)
{
int val = 0;
for(int i = 0; i < Text.Length; i++)
{
char c = Text[i];
if (c >= '0' && c <= '9')
{
val *= 10;
//(ASCII code reference)
val += c - 48;
}
}
return val;
}
static string GetdigitFromString(string str)
{
char[] refArray = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
char[] inputArray = str.ToCharArray();
string ext = string.Empty;
foreach (char item in inputArray)
{
if (refArray.Contains(item))
{
ext += item.ToString();
}
}
return ext;
}
here is my solution
string var = "Hello345wor705Ld";
string alpha = string.Empty;
string numer = string.Empty;
foreach (char str in var)
{
if (char.IsDigit(str))
numer += str.ToString();
else
alpha += str.ToString();
}
Console.WriteLine("String is: " + alpha);
Console.WriteLine("Numeric character is: " + numer);
Console.Read();
You will have to use Regex as \d+
\d matches digits in the given string.
string s = "kg g L000145.50\r\n";
char theCharacter = '.';
var getNumbers = (from t in s
where char.IsDigit(t) || t.Equals(theCharacter)
select t).ToArray();
var _str = string.Empty;
foreach (var item in getNumbers)
{
_str += item.ToString();
}
double _dou = Convert.ToDouble(_str);
MessageBox.Show(_dou.ToString("#,##0.00"));
Using #tim-pietzcker answer from above, the following will work for PowerShell.
PS C:\> $str = '1 test'
PS C:\> [regex]::match($str,'\d+').value
1
Everyone knows how to replace a character in a string with:
string text = "Hello World!";
text = text.Replace("H","J");
but what I need is to replace multiple characters in a string
something like:
string text = textBox1.Text;
text = text.Replace("a","b")
text = text.Replace("b","a")
now the result is aa , but if the user types ab I want the result to be ba
There's multiple ways to do this.
Using a loop
char[] temp = input.ToCharArray();
for (int index = 0; index < temp.Length; index++)
switch (temp[index])
{
case 'a':
temp[index] = 'b';
break;
case 'b':
temp[index] = 'a';
break;
}
string output = new string(temp);
This will simply copy the string to a character array, fix each character by itself, then convert the array back into a string. No risk of getting any of the characters confused with any of the others.
Using a regular expression
You can exploit this overload of Regex.Replace:
public static string Replace(
string input,
string pattern,
MatchEvaluator evaluator
)
This takes a delegate that will be called for each match, and return the final result. The delegate is responsible for returning what each match should be replaced with.
string output = Regex.Replace(input, ".", ma =>
{
if (ma.Value == "a")
return "b";
if (ma.Value == "b")
return "a";
return ma.Value;
});
For your particular requirement I would suggest you to use like the following:
string input = "abcba";
string outPut=String.Join("",input.ToCharArray()
.Select(x=> x=='a'? x='b':
(x=='b'?x='a':x))
.ToArray());
The output string will be bacab for this particular input
Do not call String.Replace multiple times for the same string! It creates a new string every time (also it has to cycle through the whole string every time) causing memory pressure and processor time waste if used a lot.
What you could do:
Create a new char array with the same length as the input string. Iterate over all chars of the input strings. For every char, check whether it should be replaced. If it should be replaced, write the replacement into the char array you created earlier, otherwise write the original char into that array. Then create a new string using that char array.
string inputString = "aabbccdd";
char[] chars = new char[inputString.Length];
for (int i = 0; i < inputString.Length; i++)
{
if (inputString[i] == 'a')
{
chars[i] = 'b';
}
else if (inputString[i] == 'b')
{
chars[i] = 'a';
}
else
{
chars[i] = inputString[i];
}
}
string outputString = new string(chars);
Consider using a switch when intending to replace a lot of different characters.
Use should use StringBuilder when you are concatenating many strings in a loop like this, so I suggest the following solution:
StringBuilder sb = new StringBuilder(text.Length);
foreach(char c in text)
{
sb.Append(c == 'a' ? 'b' : 'a');
}
var result = sb.ToString();
I need to alternate the case in a sentence and I don't know how to.
For example:
thequickbrownfoxjumpsoverthelazydog
to
GoDyZaLeHtReVoSpMuJxOfNwOrBkCiUqEhT
this is my code so far
Console.WriteLine("Please enter a sentence:");
string text = Console.ReadLine();
text = text.Replace(" ", "");
char[] reversed = text.ToCharArray();//String to char
Array.Reverse(reversed);//Reverses char
new string(reversed);//Char to string
Console.WriteLine(reversed);
Console.ReadLine();
Please note that there are no spaces for a reason as that's also part of the homework task.
A string is immutable, so, you need to convert it to a char[].
char[] characters = text.ToCharArray();
for (int i = 0; i < characters.Length; i+=2) {
characters[i] = char.ToUpper(characters[i]);
}
text = new string(characters);
There is no point to reverse your string. Just upper case your even number indexed characters in your string.
Remember, my culture is tr-TR and this String.ToUpper method works depends on your current thread culture. In this example, your output can be different than mine.
Here an example in LINQPad;
string s = "thequickbrownfoxjumpsoverthelazydog";
StringBuilder sb = new StringBuilder();
for (int i = 0; i < s.Length; i++)
{
if (i % 2 == 0)
{
sb.Append(s[i].ToString().ToUpper());
}
else
{
sb.Append(s[i].ToString());
}
}
sb.ToString().Dump();
Output will be;
ThEqUiCkBrOwNfOxJuMpSoVeRtHeLaZyDoG
Another possible solution with LINQ can be done in one line like this:
string s = "thequickbrownfoxjumpsoverthelazydog";
string result = new String(s
// take each character
.ToCharArray()
// convert every character at even index to upper
.Select ((character, index) => (index % 2) == 0 ? Char.ToUpper(character) : character)
// back to array in order to create a string
.ToArray());
Console.WriteLine(result);
The output is:
ThEqUiCkBrOwNfOxJuMpSoVeRtHeLaZyDoG
This solution uses the indexed LINQ Select clause in order to access the current index and the value that is currently projected.
A one liner:
new string(myString.Select((c, i) => i % 2 == 0 ? char.ToUpper(c) : c).ToArray())
An extension method:
public static string AltCase(this string s)
{
return new string(s.Select((c, i) => i % 2 == 0 ? char.ToUpper(c) : c).ToArray());
}
I am scraping some website content which is like this - "Company Stock Rs. 7100".
Now, what i want is to extract the numeric value from this string. I tried split but something or the other goes wrong with my regular expression.
Please let me know how to get this value.
Use:
var result = Regex.Match(input, #"\d+").Value;
If you want to find only number which is last "entity" in the string you should use this regex:
\d+$
If you want to match last number in the string, you can use:
\d+(?!\D*\d)
int val = int.Parse(Regex.Match(input, #"\d+", RegexOptions.RightToLeft).Value);
I always liked LINQ:
var theNumber = theString.Where(x => char.IsNumber(x));
Though Regex sounds like the native choice...
This code will return the integer at the end of the string. This will work better than the regular expressions in the case that there is a number somewhere else in the string.
public int getLastInt(string line)
{
int offset = line.Length;
for (int i = line.Length - 1; i >= 0; i--)
{
char c = line[i];
if (char.IsDigit(c))
{
offset--;
}
else
{
if (offset == line.Length)
{
// No int at the end
return -1;
}
return int.Parse(line.Substring(offset));
}
}
return int.Parse(line.Substring(offset));
}
If your number is always after the last space and your string always ends with this number, you can get it this way:
str.Substring(str.LastIndexOf(" ") + 1)
Here is my answer ....it is separating numeric from string using C#....
static void Main(string[] args)
{
String details = "XSD34AB67";
string numeric = "";
string nonnumeric = "";
char[] mychar = details.ToCharArray();
foreach (char ch in mychar)
{
if (char.IsDigit(ch))
{
numeric = numeric + ch.ToString();
}
else
{
nonnumeric = nonnumeric + ch.ToString();
}
}
int i = Convert.ToInt32(numeric);
Console.WriteLine(numeric);
Console.WriteLine(nonnumeric);
Console.ReadLine();
}
}
}
You can use \d+ to match the first occurrence of a number:
string num = Regex.Match(input, #"\d+").Value;
there is a String which contains some # characters, i want to find " # " in my string and remove them, but it also finds and removes these ones: "#"
int atsignPlace = str.IndexOf(" # ");
while (atsignPlace >= 0)
{
str = str.Remove(atsignPlace,3);
atsignPlace = str.IndexOf(" # ");
}
i tried this code, but it removes nothing, so it always finds first '#' ,which makes it an infinite loop.
int atsignPlace = str.IndexOf(" #");
while (atsignPlace >= 0)
{
if( atsignPlace+1 < str.Length && str[atsignPlace+1] == ' ' )
str = str.Remove(atsignPlace,3);
atsignPlace = str.IndexOf(" # ");
}
Replace method also doesn't work correct.
str = str.Replace(" # ", String.Empty);
maybe there is a problem with '#' character.
the input string is a sql query, i am trying to remove some parameters from it.
[ i have used try-catch for exceptions ]
Your code works fine. Short but complete program to demonstrate:
using System;
class Test
{
static void Main()
{
string before = "xyz # abc#123";
string after = CustomRemove(before);
Console.WriteLine(after); // Prints xyzabc#123
}
static string CustomRemove(string text)
{
int atSignIndex = text.IndexOf(" # ");
while (atSignIndex >= 0)
{
text = text.Remove(atSignIndex, 3);
atSignIndex = text.IndexOf(" # ");
}
return text;
}
}
EDIT: Of course, Replace works fine too:
using System;
class Test
{
static void Main()
{
string before = "xyz # abc#123";
string after = before.Replace(" # ", "");
Console.WriteLine(after); // Prints xyzabc#123
}
}
If you're still seeing a problem with either of these, then the issue is in how you're using this code, not in the code itself.
One guess: you might have non-printed characters within the " # " which is preventing them from being removed. But you haven't really given us enough information to say. A short but complete program demonstrating it not working would help...
Keep it simple:
string result = input.Replace(" # ", String.Empty);
MSDN: String.Replace Method (String, String)
I would use regex to make sure that you get any number of whitespaces:
Regex.Replace(input, #"\s+#\s+", m => string.Empty);
string LclString = "#12 # 123#123 # #";
LclString = LclString.Replace(" # ", " ");
Yields this:
#12 123#123 #