c# - How to check whether a string contains at least one number

Check String contains at least a number
The String represents text as a sequence of UTF-16 code units. The String is a sequential collection of characters that is used to represent text. The String is a sequential collection of System.Char objects.

The following .net c# tutorial code demonstrates how we can check whether a String object contains at least a number. In this .net c# tutorial code we will determine whether a String instance contains at least a number or digit. Here we check this using the Enumerable Any() method.

The Enumerable Any() method determines whether any element of a sequence exists or satisfies a condition. So using this Any() method we test each character of the String object that which character is a digit. If it finds an element is a digit then it returns true otherwise it returns false. In this way, we can determine whether a String object contains at least a number/digit or not.

The Enumerable Any() method returns true if the source sequence is not empty and at least one of its elements passes the test in the specified predicate otherwise it returns false. The Any() method throws ArgumentNullException if the source or predicate is null.
string-contains-numbers.aspx

<%@ Page Language="C#" AutoEventWireup="true"%>

<!DOCTYPE html>  
<script runat="server"> 
    protected void Button1_Click(object sender, System.EventArgs e)  
    {
        //this section create string variables.
        string stringVal = "this is a sample string without number";
        string stringWithNumber = "this is a sample 3 string 7 with number 5";

        Label1.Text = "string..................<br />";
        Label1.Text += "stringVal: " + stringVal;
        Label1.Text += "<br />stringWithNumber: " + stringWithNumber;

        //this line check string contains any digit/numeric value/number.
        Boolean result = stringVal.Any(char.IsDigit);

        //this line check string contains any digit/numeric value/number.
        Boolean result2 = stringWithNumber.Any(char.IsDigit);

        Label1.Text += "<br /><br />stringVal contains any number (digit, numeric value)?.........";
        Label1.Text += result.ToString();

        Label1.Text += "<br /><br />stringWithNumber contains any number (digit, numeric value)?...........";
        Label1.Text += result2.ToString();
    }  
</script>  
  
<html xmlns="http://www.w3.org/1999/xhtml">  
<head id="Head1" runat="server">  
    <title>c# example - string contains numbers</title>  
</head>  
<body>  
    <form id="form1" runat="server">  
    <div>  
        <h2 style="color:MidnightBlue; font-style:italic;">  
            c# example - string contains numbers
        </h2>  
        <hr width="550" align="left" color="Gainsboro" />  
        <asp:Label   
            ID="Label1"   
            runat="server"  
            Font-Size="Large"
            >  
        </asp:Label>  
        <br /><br />
        <asp:Button   
            ID="Button1"   
            runat="server"   
            Text="string contains numbers"  
            OnClick="Button1_Click"
            Height="40"  
            Font-Bold="true"  
            />  
    </div>  
    </form>  
</body>  
</html>
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