Find and extract a number from a string

Question

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

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Extension method to get all positive numbers contained in a string       public static List lt long gt  Numbers this string str                var nums   new List lt long gt             var start   -1          for  int i   0  i  lt  str Length  i                          if  start  lt  0  amp  amp  Char IsDigit str i                                  start   i                            else if  start  gt   0  amp  amp   Char IsDigit str i                                  nums Add long Parse str Substring start  i - start                     start   -1                                  if  start  gt   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

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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    quot MARCH-14-Tue quot   string splitPattern     quot    d  quot   string   result   Regex Split dateText  splitPattern   var finalresult   string Join  quot  quot   result Where e   gt   String IsNullOrEmpty e     int DayDateInt   0   int TryParse finalresult  out DayDateInt

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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

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string input    Hello 20  I am 30 and he is 40    var numbers   Regex Matches input     d    OfType lt Match gt    Select m   gt  int Parse m Value   ToArray

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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

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Based on the last sample I created a method    private string GetNumberFromString string sLongString  int iLimitNumbers        string sReturn    NA       int iNumbersCounter   0      int iCharCounter   0        string sAlphaChars   string Empty      string sNumbers   string Empty      foreach  char str in sLongString                if  char IsDigit str                         sNumbers    str ToString                iNumbersCounter                if  iNumbersCounter    iLimitNumbers                                return sReturn   sNumbers                                  else                       sAlphaChars    str ToString                iCharCounter                   reset the counter              iNumbersCounter   0                       return sReturn

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string verificationCode   dmdsnjds5344gfgk65585               string code                   Regex r1   new Regex    d               Match m1   r1 Match verificationCode              while  m1 Success                                code    m1 Value                  m1   m1 NextMatch

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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

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go through the string and use Char IsDigit  string a    str123   string b   string Empty  int val   for  int i 0  i lt  a Length  i          if  Char IsDigit a i            b    a i      if  b Length gt 0      val   int Parse b

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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

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You can do this using String property like below    return new String input Where Char IsDigit  ToArray        which gives only number from string

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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

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var match Regex Match   a99b     d     if match Success        int val      if int TryParse match Value out val                   val is set

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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  quot anything 876 8 anything quot     quot  d     d  quot   Value               Console WriteLine Regex Match  quot anything 876 anything quot     quot  d     d  quot   Value               Console WriteLine Regex Match  quot  876435 quot     quot  d     d  quot   Value               Console WriteLine Regex Match  quot  876 435 quot     quot  d     d  quot   Value                      results     quot anything 876 8 anything quot      gt    876 8  quot anything 876 anything quot      gt    876  quot  876435 quot      gt    876435  quot  876 435 quot      gt    876 435  Sample    https   dotnetfiddle net IrtqVt

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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  gt    0   amp  amp  c  lt    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

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You can also try this  string Join null System Text RegularExpressions Regex Split expr       d

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Here is my Algorithm        Fast  C Language friendly     public static int GetNumber string Text                int val   0          for int i   0  i  lt  Text Length  i                          char c   Text i               if  c  gt    0   amp  amp  c  lt    9                                 val    10                     ASCII code reference                  val    c - 48                                  return val

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Here s how I cleanse phone numbers to get the digits only   string numericPhone   new String phone Where Char IsDigit  ToArray

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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   gt  x  gt    0   amp  amp  x  lt    9   ToArray      var numericVal   Int32 Parse numbersFromString

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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   gt   char IsDigit x                         TakeWhile x   gt  char IsDigit x                         ToArray     out result     Examples   string input    123 foo 456      123 string input    foo 456          456 string input    123 foo          123

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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

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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

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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

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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

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What I use to get Phone Numbers without any punctuation     var phone     787  763-6511    string Join     phone ToCharArray   Where Char IsDigit        result  7877636511

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Using  tim-pietzcker answer from above  the following will work for PowerShell   PS C   gt   str    1 test  PS C   gt   regex   match  str   d    value 1

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You will have to use Regex as  d    d matches digits in the given string

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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

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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

[c#] Find and extract a number from a string

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