CODEWITHSUNDEEP
c#stringinteger
Butters
Butters

Reputation: 997

Determine if a string is greater than another string

I have two strings

 string A = "1.0.0.0";
 string B = "1.0.0.1";

I need to evaluate somehow that B is greater than A (version wise) either converting those two strings to integers or decimals or something.

I tried the following 

Decimal S = Convert.ToDecimal(A);
int S = Convert.ToInt32(A);

but keep getting the following error, "Input string was not in a correct format."

Any help will be appreciated.

Upvotes: 4

Views: 13590

Answers (6)

Stas
Stas

Reputation: 286

You can take a look at System.Version class. If the strings are in this format or can be converted to a version.

Version have comparers

Upvotes: 3

Jota Villalobos
Jota Villalobos

Reputation: 11

Instead of using VersionClass a fast approach would be something like this.

string A = "1.0.0.0";
string B = "1.0.0.1";

int versionA = Convert.ToInt32(A.Replace(".", string.Empty));
int versionB = Convert.ToInt32(B.Replace(".", string.Empty));

if (b>a)
//something will happen here

Replace changes the first string to the second one in this case string.Empty equals to "".

Upvotes: -2

tnw
tnw

Reputation: 13877

See the Version Class.

You're able to do something like this:

Version a = new Version("1.0.0.0");
Version b = new Version("1.0.0.1");

if (b>a) //evaluates to true
    blah blah blah

I haven't personally tested this exact scenario, but the Version class allows you to use comparison operators like I've shown here.

Upvotes: 20

Oded
Oded

Reputation: 498972

If your string has at most 4 numeric parts (separated by .), you can use the Version class to get a strongly typed entity that corresponds to these strings. Version implements the different comparison operators (==, >, < etc...) in the expected manner, so you can find out which is greater:

var a = new Version(A);
var b = new Version(B);

if(a > b)
  // a is larger
else if (a < b)
  // b is larger
else
  // they are identical

If there are more than 4 parts, you will need to split each string to its numeric components, convert each one to a numeric equivalent and compare the two resulting collections.

Something like:

var aParts = A.Split('.');
var bParts = B.Split('.');

// assumes the string have the same number of parts
for(int i = 0; i < aParts.Length; i++)
{
  var currA = int.Parse(aParts[i]);
  var currB = int.Parse(bParts[i]);

  if(currA == currB)
    continue;

  if(currA > currB)
    // A is greater than B      
  else
    // B is greater than A
}

Upvotes: 3

redtuna
redtuna

Reputation: 4600

Split on the ".". Then convert each part to an int. Starting from the left: if A's fragment is lower, then report that A is first. If B's fragment is lower, then report that B is first. Otherwise, move to the next fragment. If you're at the last fragment already, report that they are equal.

If your strings have at most four parts (like version numbers), then as others suggested it's easier to use the System.Version class.

Upvotes: 1

Jehof
Jehof

Reputation: 35544

If you want to compare version strings in .NET, then you can use the Version class.

Version version = new Version("1.0.0.0");
Version otherVersion = new Version(""1.0.0.1");

The class provides operators to check if a version is greater or lesser than another.

Upvotes: 1

Related Questions