public static decimal Min(this IEnumerable <decimal> source)
{
if (source.TryGetSpan(out ReadOnlySpan <decimal> span))
{
return(Min(span));
}
decimal value;
using (IEnumerator <decimal> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = e.Current;
while (e.MoveNext())
{
decimal x = e.Current;
if (x < value)
{
value = x;
}
}
}
return(value);
}
public static double Average <TSource>(this IEnumerable <TSource> source, Func <TSource, double> selector)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (selector == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.selector);
}
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
double sum = selector(e.Current);
long count = 1;
while (e.MoveNext())
{
// There is an opportunity to short-circuit here, in that if e.Current is
// ever NaN then the result will always be NaN. Assuming that this case is
// rare enough that not checking is the better approach generally.
sum += selector(e.Current);
++count;
}
return(sum / count);
}
}
public static double Min(this IEnumerable <double> source)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
double value;
using (IEnumerator <double> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = e.Current;
while (e.MoveNext())
{
double x = e.Current;
if (x < value)
{
value = x;
}
else if (double.IsNaN(x))
{
return(x);
}
}
}
return(value);
}
public static long Max(this IEnumerable <long> source)
{
if (source.TryGetSpan(out ReadOnlySpan <long> span))
{
return(Max(span));
}
long value;
using (IEnumerator <long> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = e.Current;
while (e.MoveNext())
{
long x = e.Current;
if (x > value)
{
value = x;
}
}
}
return(value);
}
public static long Min(this IEnumerable <long> source)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (source.GetType() == typeof(long[]))
{
return(Min((long[])source));
}
long value;
using (IEnumerator <long> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = e.Current;
while (e.MoveNext())
{
long x = e.Current;
if (x < value)
{
value = x;
}
}
}
return(value);
}
public static decimal Min <TSource>(this IEnumerable <TSource> source, Func <TSource, decimal> selector)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (selector == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.selector);
}
decimal value;
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = selector(e.Current);
while (e.MoveNext())
{
decimal x = selector(e.Current);
if (x < value)
{
value = x;
}
}
}
return(value);
}
public static TSource Aggregate <TSource>(this IEnumerable <TSource> source, Func <TSource, TSource, TSource> func)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (func == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.func);
}
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
TSource result = e.Current;
while (e.MoveNext())
{
result = func(result, e.Current);
}
return(result);
}
}
public static double Average(this IEnumerable <long> source)
{
if (source.TryGetSpan(out ReadOnlySpan <long> span))
{
return(Average(span));
}
using (IEnumerator <long> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
long sum = e.Current;
long count = 1;
checked
{
while (e.MoveNext())
{
sum += e.Current;
++count;
}
}
return((double)sum / count);
}
}
public static int Max(this IEnumerable <int> source)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (source.GetType() == typeof(int[]))
{
return(Max((int[])source));
}
int value;
using (IEnumerator <int> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = e.Current;
while (e.MoveNext())
{
int x = e.Current;
if (x > value)
{
value = x;
}
}
}
return(value);
}
public static decimal Average <TSource>(this IEnumerable <TSource> source, Func <TSource, decimal> selector)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (selector == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.selector);
}
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
decimal sum = selector(e.Current);
long count = 1;
while (e.MoveNext())
{
sum += selector(e.Current);
++count;
}
return(sum / count);
}
}
private static double Average(ReadOnlySpan <int> span)
{
if (span.IsEmpty)
{
ThrowHelper.ThrowNoElementsException();
}
long sum = 0;
int i = 0;
if (Vector.IsHardwareAccelerated && span.Length >= Vector <int> .Count)
{
Vector <long> sums = default;
do
{
Vector.Widen(new Vector <int>(span.Slice(i)), out Vector <long> low, out Vector <long> high);
sums += low;
sums += high;
i += Vector <int> .Count;
}while (i <= span.Length - Vector <int> .Count);
sum += Vector.Sum(sums);
}
for (; (uint)i < (uint)span.Length; i++)
{
sum += span[i];
}
return((double)sum / span.Length);
}
public static decimal Average(this IEnumerable <decimal> source)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
using (IEnumerator <decimal> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
decimal sum = e.Current;
long count = 1;
while (e.MoveNext())
{
sum += e.Current;
++count;
}
return(sum / count);
}
}
public static decimal Average(this IEnumerable <decimal> source)
{
if (source.TryGetSpan(out ReadOnlySpan <decimal> span))
{
if (span.IsEmpty)
{
ThrowHelper.ThrowNoElementsException();
}
return(Sum(span) / span.Length);
}
using (IEnumerator <decimal> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
decimal sum = e.Current;
long count = 1;
while (e.MoveNext())
{
sum += e.Current;
++count;
}
return(sum / count);
}
}
public static double Average(this IEnumerable <double> source)
{
if (source.TryGetSpan(out ReadOnlySpan <double> span))
{
if (span.IsEmpty)
{
ThrowHelper.ThrowNoElementsException();
}
return(Sum(span) / span.Length);
}
using (IEnumerator <double> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
double sum = e.Current;
long count = 1;
while (e.MoveNext())
{
// There is an opportunity to short-circuit here, in that if e.Current is
// ever NaN then the result will always be NaN. Assuming that this case is
// rare enough that not checking is the better approach generally.
sum += e.Current;
++count;
}
return(sum / count);
}
}
public static decimal Min(this IEnumerable <decimal> source)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
decimal value;
using (IEnumerator <decimal> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = e.Current;
while (e.MoveNext())
{
decimal x = e.Current;
if (x < value)
{
value = x;
}
}
}
return(value);
}
private static TResult Average <TSource, TAccumulator, TResult>(this IEnumerable <TSource> source)
where TSource : struct, INumber <TSource>
where TAccumulator : struct, INumber <TAccumulator>
where TResult : struct, INumber <TResult>
{
if (source.TryGetSpan(out ReadOnlySpan <TSource> span))
{
if (span.IsEmpty)
{
ThrowHelper.ThrowNoElementsException();
}
return(TResult.CreateChecked(Sum <TSource, TAccumulator>(span)) / TResult.CreateChecked(span.Length));
}
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
TAccumulator sum = TAccumulator.CreateChecked(e.Current);
long count = 1;
while (e.MoveNext())
{
checked { sum += TAccumulator.CreateChecked(e.Current); }
count++;
}
return(TResult.CreateChecked(sum) / TResult.CreateChecked(count));
}
}
public static double Average(this IEnumerable <int> source)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
using (IEnumerator <int> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
long sum = e.Current;
long count = 1;
checked
{
while (e.MoveNext())
{
sum += e.Current;
++count;
}
}
return((double)sum / count);
}
}
public static TResult?Min <TSource, TResult>(this IEnumerable <TSource> source, Func <TSource, TResult> selector)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (selector == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.selector);
}
TResult?value = default;
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (value == null)
{
do
{
if (!e.MoveNext())
{
return(value);
}
value = selector(e.Current);
}while (value == null);
Comparer <TResult> comparer = Comparer <TResult> .Default;
while (e.MoveNext())
{
TResult x = selector(e.Current);
if (x != null && comparer.Compare(x, value) < 0)
{
value = x;
}
}
}
else
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = selector(e.Current);
while (e.MoveNext())
{
TResult x = selector(e.Current);
if (Comparer <TResult> .Default.Compare(x, value) < 0)
{
value = x;
}
}
}
}
return(value);
}
public static TSource Min <TSource>(this IEnumerable <TSource> source)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
Comparer <TSource> comparer = Comparer <TSource> .Default;
TSource value = default(TSource);
if (value == null)
{
using (IEnumerator <TSource> e = source.GetEnumerator())
{
do
{
if (!e.MoveNext())
{
return(value);
}
value = e.Current;
}while (value == null);
while (e.MoveNext())
{
TSource x = e.Current;
if (x != null && comparer.Compare(x, value) < 0)
{
value = x;
}
}
}
}
else
{
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = e.Current;
while (e.MoveNext())
{
TSource x = e.Current;
if (comparer.Compare(x, value) < 0)
{
value = x;
}
}
}
}
return(value);
}
public static double Average(this IEnumerable <int> source)
{
if (source.TryGetSpan(out ReadOnlySpan <int> span))
{
// Int32 is special-cased separately from the rest of the types as it can be vectorized:
// with at most Int32.MaxValue values, and with each being at most Int32.MaxValue, we can't
// overflow a long accumulator, and order of operations doesn't matter.
if (span.IsEmpty)
{
ThrowHelper.ThrowNoElementsException();
}
long sum = 0;
int i = 0;
if (Vector.IsHardwareAccelerated && span.Length >= Vector <int> .Count)
{
Vector <long> sums = default;
do
{
Vector.Widen(new Vector <int>(span.Slice(i)), out Vector <long> low, out Vector <long> high);
sums += low;
sums += high;
i += Vector <int> .Count;
}while (i <= span.Length - Vector <int> .Count);
sum += Vector.Sum(sums);
}
for (; (uint)i < (uint)span.Length; i++)
{
sum += span[i];
}
return((double)sum / span.Length);
}
using (IEnumerator <int> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
long sum = e.Current;
long count = 1;
while (e.MoveNext())
{
checked { sum += e.Current; }
count++;
}
return((double)sum / count);
}
}
public static TSource Single <TSource>(this IEnumerable <TSource> source)
{
TSource?single = source.TryGetSingle(out bool found);
if (!found)
{
ThrowHelper.ThrowNoElementsException();
}
return(single !);
}
public static TSource First <TSource>(this IEnumerable <TSource> source)
{
TSource first = source.TryGetFirst(out bool found);
if (!found)
{
ThrowHelper.ThrowNoElementsException();
}
return(first);
}
public static float Min <TSource>(this IEnumerable <TSource> source, Func <TSource, float> selector)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (selector == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.selector);
}
float value;
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = selector(e.Current);
if (float.IsNaN(value))
{
return(value);
}
while (e.MoveNext())
{
float x = selector(e.Current);
if (x < value)
{
value = x;
}
// Normally NaN < anything is false, as is anything < NaN
// However, this leads to some irksome outcomes in Min and Max.
// If we use those semantics then Min(NaN, 5.0) is NaN, but
// Min(5.0, NaN) is 5.0! To fix this, we impose a total
// ordering where NaN is smaller than every value, including
// negative infinity.
// Not testing for NaN therefore isn't an option, but since we
// can't find a smaller value, we can short-circuit.
else if (float.IsNaN(x))
{
return(x);
}
}
}
return(value);
}
private static long Min(long[] array)
{
if (array.Length == 0)
{
ThrowHelper.ThrowNoElementsException();
}
// Vectorize the search if possible.
int index;
long value;
if (Vector.IsHardwareAccelerated && array.Length >= Vector <long> .Count * 2)
{
// The array is at least two vectors long. Create a vector from the first N elements,
// and then repeatedly compare that against the next vector from the array. At the end,
// the resulting vector will contain the minimum values found, and we then need only
// to find the min of those.
var mins = new Vector <long>(array);
index = Vector <long> .Count;
do
{
mins = Vector.Min(mins, new Vector <long>(array, index));
index += Vector <long> .Count;
}while (index + Vector <long> .Count <= array.Length);
value = mins[0];
for (int i = 1; i < Vector <long> .Count; i++)
{
if (mins[i] < value)
{
value = mins[i];
}
}
}
else
{
value = array[0];
index = 1;
}
// Iterate through the remaining elements, comparing against the min.
for (int i = index; (uint)i < (uint)array.Length; i++)
{
if (array[i] < value)
{
value = array[i];
}
}
return(value);
}
private static long Max(ReadOnlySpan <long> span)
{
if (span.IsEmpty)
{
ThrowHelper.ThrowNoElementsException();
}
// Vectorize the search if possible.
int index;
long value;
if (Vector.IsHardwareAccelerated && span.Length >= Vector <long> .Count * 2)
{
// The span is at least two vectors long. Create a vector from the first N elements,
// and then repeatedly compare that against the next vector from the span. At the end,
// the resulting vector will contain the maximum values found, and we then need only
// to find the max of those.
var maxes = new Vector <long>(span);
index = Vector <long> .Count;
do
{
maxes = Vector.Max(maxes, new Vector <long>(span.Slice(index)));
index += Vector <long> .Count;
}while (index + Vector <long> .Count <= span.Length);
value = maxes[0];
for (int i = 1; i < Vector <long> .Count; i++)
{
if (maxes[i] > value)
{
value = maxes[i];
}
}
}
else
{
value = span[0];
index = 1;
}
// Iterate through the remaining elements, comparing against the max.
for (int i = index; (uint)i < (uint)span.Length; i++)
{
if (span[i] > value)
{
value = span[i];
}
}
return(value);
}
public static double Max <TSource>(this IEnumerable <TSource> source, Func <TSource, double> selector)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (selector == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.selector);
}
double value;
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = selector(e.Current);
// As described in a comment on Min(this IEnumerable<double>) NaN is ordered
// less than all other values. We need to do explicit checks to ensure this, but
// once we've found a value that is not NaN we need no longer worry about it,
// so first loop until such a value is found (or not, as the case may be).
while (double.IsNaN(value))
{
if (!e.MoveNext())
{
return(value);
}
value = selector(e.Current);
}
while (e.MoveNext())
{
double x = selector(e.Current);
if (x > value)
{
value = x;
}
}
}
return(value);
}
private static double Average(ReadOnlySpan <long> span)
{
if (span.IsEmpty)
{
ThrowHelper.ThrowNoElementsException();
}
long sum = span[0];
for (int i = 1; i < span.Length; i++)
{
checked { sum += span[i]; }
}
return((double)sum / span.Length);
}
private static double Max(ReadOnlySpan <double> span)
{
if (span.IsEmpty)
{
ThrowHelper.ThrowNoElementsException();
}
int i;
for (i = 0; i < span.Length && double.IsNaN(span[i]); i++)
{
;
}
if (i == span.Length)
{
return(span[^ 1]);
public static float Max <TSource>(this IEnumerable <TSource> source, Func <TSource, float> selector)
{
if (source == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
}
if (selector == null)
{
ThrowHelper.ThrowArgumentNullException(ExceptionArgument.selector);
}
float value;
using (IEnumerator <TSource> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = selector(e.Current);
while (float.IsNaN(value))
{
if (!e.MoveNext())
{
return(value);
}
value = selector(e.Current);
}
while (e.MoveNext())
{
float x = selector(e.Current);
if (x > value)
{
value = x;
}
}
}
return(value);
}
public static double Max(this IEnumerable <double> source)
{
if (source.TryGetSpan(out ReadOnlySpan <double> span))
{
return(Max(span));
}
double value;
using (IEnumerator <double> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
ThrowHelper.ThrowNoElementsException();
}
value = e.Current;
// As described in a comment on Min(this IEnumerable<double>) NaN is ordered
// less than all other values. We need to do explicit checks to ensure this, but
// once we've found a value that is not NaN we need no longer worry about it,
// so first loop until such a value is found (or not, as the case may be).
while (double.IsNaN(value))
{
if (!e.MoveNext())
{
return(value);
}
value = e.Current;
}
while (e.MoveNext())
{
double x = e.Current;
if (x > value)
{
value = x;
}
}
}
return(value);
}