Jeff, your code is nice but could be clearer with constants (as suggested in Code Complete).
const int SECOND = 1;
const int MINUTE = 60 * SECOND;
const int HOUR = 60 * MINUTE;
const int DAY = 24 * HOUR;
const int MONTH = 30 * DAY;
var ts = new TimeSpan(DateTime.UtcNow.Ticks - yourDate.Ticks);
double delta = Math.Abs(ts.TotalSeconds);
if (delta < 1 * MINUTE)
return ts.Seconds == 1 ? "one second ago" : ts.Seconds + " seconds ago";
if (delta < 2 * MINUTE)
return "a minute ago";
if (delta < 45 * MINUTE)
return ts.Minutes + " minutes ago";
if (delta < 90 * MINUTE)
return "an hour ago";
if (delta < 24 * HOUR)
return ts.Hours + " hours ago";
if (delta < 48 * HOUR)
return "yesterday";
if (delta < 30 * DAY)
return ts.Days + " days ago";
if (delta < 12 * MONTH)
{
int months = Convert.ToInt32(Math.Floor((double)ts.Days / 30));
return months <= 1 ? "one month ago" : months + " months ago";
}
else
{
int years = Convert.ToInt32(Math.Floor((double)ts.Days / 365));
return years <= 1 ? "one year ago" : years + " years ago";
}
@Joel's answer is pretty close, but it will fail in the following cases:
// Whitespace strings:
IsNumeric(' ') == true;
IsNumeric('\t\t') == true;
IsNumeric('\n\r') == true;
// Number literals:
IsNumeric(-1) == false;
IsNumeric(0) == false;
IsNumeric(1.1) == false;
IsNumeric(8e5) == false;
Some time ago I had to implement an IsNumeric
function, to find out if a variable contained a numeric value, regardless of its type, it could be a String
containing a numeric value (I had to consider also exponential notation, etc.), a Number
object, virtually anything could be passed to that function, I couldn't make any type assumptions, taking care of type coercion (eg. +true == 1;
but true
shouldn't be considered as "numeric"
).
I think is worth sharing this set of +30 unit tests made to numerous function implementations, and also share the one that passes all my tests:
function isNumeric(n) {
return !isNaN(parseFloat(n)) && isFinite(n);
}
P.S. isNaN & isFinite have a confusing behavior due to forced conversion to number. In ES6, Number.isNaN & Number.isFinite would fix these issues. Keep that in mind when using them.
Update :
Here's how jQuery does it now (2.2-stable):
isNumeric: function(obj) {
var realStringObj = obj && obj.toString();
return !jQuery.isArray(obj) && (realStringObj - parseFloat(realStringObj) + 1) >= 0;
}
Update :
Angular 4.3:
export function isNumeric(value: any): boolean {
return !isNaN(value - parseFloat(value));
}
Best Solution
Look at
Math.Round(decimal)
or the overload which takes aMidpointRounding
argument.Of course, you'll need to parse and format the value to get it from/to text. If this is input entered by the user, you should probably use
decimal.TryParse
, using the return value to determine whether or not the input was valid.