You can save about 10% by calling Double.TryParse
with specific cached instances of NumberStyles
and IFormatProvider
(i.e. CultureInfo
):
var style = System.Globalization.NumberStyles.AllowDecimalPoint;
var culture = System.Globalization.CultureInfo.InvariantCulture;
double.TryParse("1.34515", style, culture, out x);
Both Convert.ToDouble
and Double.Parse
or Double.TryParse
have to assume the input can be in any format. If you know for certain that your input has a specific format, you can write a custom parser that performs much better.
Here's one that converts to decimal
. Conversion to double
is similar.
static decimal CustomParseDecimal(string input) {
long n = 0;
int decimalPosition = input.Length;
for (int k = 0; k < input.Length; k++) {
char c = input[k];
if (c == '.')
decimalPosition = k + 1;
else
n = (n * 10) + (int)(c - '0');
}
return new decimal((int)n, (int)(n >> 32), 0, false, (byte)(input.Length - decimalPosition));
}
My benchmarks show this to be about 5 times faster than the original for decimal
, and up to 12 times if you use ints.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…