How could I convert data from string to long in c#

How could i convert data from string to long in C#?

I have data

String strValue[i] ="1100.25"; 

now i want it in

long l1; 

8 Answers

If you want to get the integer part of that number you must first convert it to a floating number then cast to long.

long l1 = (long)Convert.ToDouble("1100.25"); 

You can use Math class to round up the number as you like, or just truncate...

• Math.Round
• Math.Ceil

You can also use long.TryParse and long.Parse.

long l1; l1 = long.Parse("1100.25"); //or long.TryParse("1100.25", out l1); 

l1 = Convert.ToInt64(strValue)

Though the example you gave isn't an integer, so I'm not sure why you want it as a long.

long l1 = Convert.ToInt64(strValue); 

That should do it.

You won't be able to convert it directly to long because of the decimal point i think you should convert it into decimal and then convert it into long something like this:

String strValue[i] = "1100.25"; long l1 = Convert.ToInt64(Convert.ToDecimal(strValue)); 

hope this helps!

long is internally represented as System.Int64 which is a 64-bit signed integer. The value you have taken "1100.25" is actually decimal and not integer hence it can not be converted to long.

You can use:

String strValue = "1100.25"; decimal lValue = Convert.ToDecimal(strValue); 

to convert it to decimal value

You can also do using Int64.TryParse Method. It will return '0' if their is any string value but did not generate an error.

Int64 l1; Int64.TryParse(strValue, out l1); 

You can create your own conversion function:

 static long ToLong(string lNumber) { if (string.IsNullOrEmpty(lNumber)) throw new Exception("Not a number!"); char[] chars = lNumber.ToCharArray(); long result = 0; bool isNegative = lNumber[0] == '-'; if (isNegative && lNumber.Length == 1) throw new Exception("- Is not a number!"); for (int i = (isNegative ? 1:0); i < lNumber.Length; i++) { if (!Char.IsDigit(chars[i])) { if (chars[i] == '.' && i < lNumber.Length - 1 && Char.IsDigit(chars[i+1])) { var firstDigit = chars[i + 1] - 48; return (isNegative ? -1L:1L) * (result + ((firstDigit < 5) ? 0L : 1L)); } throw new InvalidCastException($" {lNumber} is not a valid number!"); } result = result * 10 + ((long)chars[i] - 48L); } return (isNegative ? -1L:1L) * result; } 

It can be improved further:

• performance wise
• make the validation stricter in the sense that it currently doesn't care if characters after first decimal aren't digits
• specify rounding behavior as parameter for conversion function. it currently does rounding