List Module
Contains operations for working with values of type list.
Functions and values
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Returns a new list that contains all pairings of elements from the first and second lists.
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Returns a new list that contains the elements of the first list followed by elements of the second.
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Full Usage:
List.average list
Parameters:
^T list
-
The input list.
Returns: ^T
The resulting average.
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Returns the average of the elements in the list.
Raises ArgumentException if
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Full Usage:
List.averageBy projection list
Parameters:
'T -> ^U
-
The function to transform the list elements into the type to be averaged.
list : 'T list
-
The input list.
Returns: ^U
The resulting average.
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Returns the average of the elements generated by applying the function to each element of the list.
Raises ArgumentException if
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Applies the given function to each element of the list. Returns
the list comprised of the results
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Divides the input list into chunks of size at most
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For each element of the list, applies the given function. Concatenates all the results and return the combined list.
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Full Usage:
List.compareWith comparer list1 list2
Parameters:
'T -> 'T -> int
-
A function that takes an element from each list and returns an int.
If it evaluates to a non-zero value iteration is stopped and that value is returned.
list1 : 'T list
-
The first input list.
list2 : 'T list
-
The second input list.
Returns: int
Returns the first non-zero result from the comparison function. If the first list has a
larger element, the return value is always positive. If the second list has a larger
element, the return value is always negative. When the elements are equal in the two
lists, 1 is returned if the first list is longer, 0 is returned if they are equal in
length, and -1 is returned when the second list is longer.
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Compares two lists using the given comparison function, element by element.
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Returns a new list that contains the elements of each the lists in order.
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Tests if the list contains the specified element.
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Applies a key-generating function to each element of a list and returns a list yielding unique keys and their number of occurrences in the original list.
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Returns a list that contains no duplicate entries according to generic hash and equality comparisons on the entries. If an element occurs multiple times in the list then the later occurrences are discarded.
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Returns a list that contains no duplicate entries according to the generic hash and equality comparisons on the keys returned by the given key-generating function. If an element occurs multiple times in the list then the later occurrences are discarded.
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Returns an empty list of the given type.
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Full Usage:
List.exactlyOne list
Parameters:
'T list
-
The input list.
Returns: 'T
The only element of the list.
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Returns the only element of the list.
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Full Usage:
List.except itemsToExclude list
Parameters:
seq<'T>
-
A sequence whose elements that also occur in the input list will cause those elements to be
removed from the result.
list : 'T list
-
A list whose elements that are not also in itemsToExclude will be returned.
Returns: 'T list
A list that contains the distinct elements of list that do not appear in itemsToExclude.
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Returns a new list with the distinct elements of the input list which do not appear in the itemsToExclude sequence, using generic hash and equality comparisons to compare values.
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Tests if any element of the list satisfies the given predicate. The predicate is applied to the elements of the input list. If any application returns true then the overall result is true and no further elements are tested. Otherwise, false is returned.
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Tests if any pair of corresponding elements of the lists satisfies the given predicate. The predicate is applied to matching elements in the two collections up to the lesser of the two lengths of the collections. If any application returns true then the overall result is true and no further elements are tested. Otherwise, if one collections is longer than the other then the ArgumentException exception is raised. Otherwise, false is returned.
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Returns a new collection containing only the elements of the collection for which the given predicate returns "true"
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Returns the first element for which the given function returns True.
Raises
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Returns the last element for which the given function returns True.
Raises
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Returns the index of the first element in the list
that satisfies the given predicate.
Raises
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Returns the index of the last element in the list
that satisfies the given predicate.
Raises
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Full Usage:
List.fold folder state list
Parameters:
'State -> 'T -> 'State
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The function to update the state given the input elements.
state : 'State
-
The initial state.
list : 'T list
-
The input list.
Returns: 'State
The final state value.
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Applies a function to each element of the collection, threading an accumulator argument
through the computation. Take the second argument, and apply the function to it
and the first element of the list. Then feed this result into the function along
with the second element and so on. Return the final result.
If the input function is
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Full Usage:
List.fold2 folder state list1 list2
Parameters:
'State -> 'T1 -> 'T2 -> 'State
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The function to update the state given the input elements.
state : 'State
-
The initial state.
list1 : 'T1 list
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The first input list.
list2 : 'T2 list
-
The second input list.
Returns: 'State
The final state value.
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Applies a function to corresponding elements of two collections, threading an accumulator argument
through the computation. The collections must have identical sizes.
If the input function is
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Full Usage:
List.foldBack folder list state
Parameters:
'T -> 'State -> 'State
-
The function to update the state given the input elements.
list : 'T list
-
The input list.
state : 'State
-
The initial state.
Returns: 'State
The state object after the folding function is applied to each element of the list.
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Applies a function to each element of the collection, starting from the end, threading an accumulator argument
through the computation. If the input function is
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Full Usage:
List.foldBack2 folder list1 list2 state
Parameters:
'T1 -> 'T2 -> 'State -> 'State
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The function to update the state given the input elements.
list1 : 'T1 list
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The first input list.
list2 : 'T2 list
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The second input list.
state : 'State
-
The initial state.
Returns: 'State
The final state value.
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Applies a function to corresponding elements of two collections, threading an accumulator argument
through the computation. The collections must have identical sizes.
If the input function is
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Tests if all elements of the collection satisfy the given predicate. The predicate is applied to the elements of the input list. If any application returns false then the overall result is false and no further elements are tested. Otherwise, true is returned.
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Tests if all corresponding elements of the collection satisfy the given predicate pairwise. The predicate is applied to matching elements in the two collections up to the lesser of the two lengths of the collections. If any application returns false then the overall result is false and no further elements are tested. Otherwise, if one collection is longer than the other then the ArgumentException exception is raised. Otherwise, true is returned.
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Applies a key-generating function to each element of a list and yields a list of unique keys. Each unique key contains a list of all elements that match to this key.
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Full Usage:
List.head list
Parameters:
'T list
-
The input list.
Returns: 'T
The first element of the list.
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Returns the first element of the list.
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Returns a new list whose elements are the corresponding elements of the input list paired with the index (from 0) of each element.
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Creates a list by calling the given generator on each index.
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Returns true if the list contains no elements, false otherwise.
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Indexes into the list. The first element has index 0.
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Applies the given function to each element of the collection. |
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Applies the given function to two collections simultaneously. The collections must have identical size. |
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Applies the given function to each element of the collection. The integer passed to the function indicates the index of element. |
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Applies the given function to two collections simultaneously. The collections must have identical size. The integer passed to the function indicates the index of element. |
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Full Usage:
List.last list
Parameters:
'T list
-
The input list.
Returns: 'T
The last element of the list.
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Returns the last element of the list.
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Returns the length of the list.
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Builds a new collection whose elements are the results of applying the given function to each of the elements of the collection.
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Builds a new collection whose elements are the results of applying the given function to the corresponding elements of the two collections pairwise.
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Full Usage:
List.map3 mapping list1 list2 list3
Parameters:
'T1 -> 'T2 -> 'T3 -> 'U
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The function to transform triples of elements from the input lists.
list1 : 'T1 list
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The first input list.
list2 : 'T2 list
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The second input list.
list3 : 'T3 list
-
The third input list.
Returns: 'U list
The list of transformed elements.
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Builds a new collection whose elements are the results of applying the given function to the corresponding elements of the three collections simultaneously.
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Full Usage:
List.mapFold mapping state list
Parameters:
'State -> 'T -> 'Result * 'State
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The function to transform elements from the input list and accumulate the final value.
state : 'State
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The initial state.
list : 'T list
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The input list.
Returns: 'Result list * 'State
The list of transformed elements, and the final accumulated value.
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Combines map and fold. Builds a new list whose elements are the results of applying the given function to each of the elements of the input list. The function is also used to accumulate a final value.
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Full Usage:
List.mapFoldBack mapping list state
Parameters:
'T -> 'State -> 'Result * 'State
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The function to transform elements from the input list and accumulate the final value.
list : 'T list
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The input list.
state : 'State
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The initial state.
Returns: 'Result list * 'State
The list of transformed elements, and the final accumulated value.
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Combines map and foldBack. Builds a new list whose elements are the results of applying the given function to each of the elements of the input list. The function is also used to accumulate a final value.
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Builds a new collection whose elements are the results of applying the given function to each of the elements of the collection. The integer index passed to the function indicates the index (from 0) of element being transformed.
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Full Usage:
List.mapi2 mapping list1 list2
Parameters:
int -> 'T1 -> 'T2 -> 'U
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The function to transform pairs of elements from the two lists and their index.
list1 : 'T1 list
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The first input list.
list2 : 'T2 list
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The second input list.
Returns: 'U list
The list of transformed elements.
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Like mapi, but mapping corresponding elements from two lists of equal length.
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Full Usage:
List.max list
Parameters:
'T list
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The input list.
Returns: 'T
The maximum element.
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Return the greatest of all elements of the list, compared via Operators.max.
Raises ArgumentException if
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Full Usage:
List.maxBy projection list
Parameters:
'T -> 'U
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The function to transform the list elements into the type to be compared.
list : 'T list
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The input list.
Returns: 'T
The maximum element.
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Returns the greatest of all elements of the list, compared via Operators.max on the function result.
Raises ArgumentException if
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Full Usage:
List.min list
Parameters:
'T list
-
The input list.
Returns: 'T
The minimum value.
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Returns the lowest of all elements of the list, compared via Operators.min.
Raises ArgumentException if
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Full Usage:
List.minBy projection list
Parameters:
'T -> 'U
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The function to transform list elements into the type to be compared.
list : 'T list
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The input list.
Returns: 'T
The minimum value.
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Returns the lowest of all elements of the list, compared via Operators.min on the function result
Raises ArgumentException if
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Full Usage:
List.ofArray array
Parameters:
'T[]
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The input array.
Returns: 'T list
The list of elements from the array.
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Builds a list from the given array.
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Builds a new list from the given enumerable object.
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Returns a list of each element in the input list and its predecessor, with the exception of the first element which is only returned as the predecessor of the second element.
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Splits the collection into two collections, containing the elements for which the given predicate returns True and False respectively. Element order is preserved in both of the created lists. |
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Returns a list with all elements permuted according to the specified permutation.
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Applies the given function to successive elements, returning the first
result where function returns
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Full Usage:
List.reduce reduction list
Parameters:
'T -> 'T -> 'T
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The function to reduce two list elements to a single element.
list : 'T list
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The input list.
Returns: 'T
The final reduced value.
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Apply a function to each element of the collection, threading an accumulator argument
through the computation. Apply the function to the first two elements of the list.
Then feed this result into the function along with the third element and so on.
Return the final result. If the input function is
Raises ArgumentException if
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Full Usage:
List.reduceBack reduction list
Parameters:
'T -> 'T -> 'T
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A function that takes in the next-to-last element of the list and the
current accumulated result to produce the next accumulated result.
list : 'T list
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The input list.
Returns: 'T
The final result of the reductions.
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Applies a function to each element of the collection, starting from the end, threading an accumulator argument
through the computation. If the input function is
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Creates a list by replicating the given initial value.
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Returns a new list with the elements in reverse order.
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Applies a function to each element of the collection, threading an accumulator argument through the computation. Take the second argument, and apply the function to it and the first element of the list. Then feed this result into the function along with the second element and so on. Returns the list of intermediate results and the final result.
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Like
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Full Usage:
List.singleton value
Parameters:
'T
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The input item.
Returns: 'T list
The result list of one item.
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Returns a list that contains one item only.
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Returns the list after removing the first N elements.
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Bypasses elements in a list while the given predicate returns True, and then returns the remaining elements of the list.
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This is a stable sort, i.e. the original order of equal elements is preserved.
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Sorts the given list using keys given by the given projection. Keys are compared using Operators.compare. This is a stable sort, i.e. the original order of equal elements is preserved.
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Sorts the given list in descending order using keys given by the given projection. Keys are compared using Operators.compare. This is a stable sort, i.e. the original order of equal elements is preserved.
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This is a stable sort, i.e. the original order of equal elements is preserved.
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Sorts the given list using the given comparison function. This is a stable sort, i.e. the original order of equal elements is preserved.
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Splits a list into two lists, at the given index.
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Splits the input list into at most
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Full Usage:
List.sum list
Parameters:
^T list
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The input list.
Returns: ^T
The resulting sum.
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Returns the sum of the elements in the list.
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Full Usage:
List.sumBy projection list
Parameters:
'T -> ^U
-
The function to transform the list elements into the type to be summed.
list : 'T list
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The input list.
Returns: ^U
The resulting sum.
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Returns the sum of the results generated by applying the function to each element of the list.
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Returns the list after removing the first element.
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Returns the first N elements of the list.
Throws
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Returns a list that contains all elements of the original list while the given predicate returns True, and then returns no further elements.
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Full Usage:
List.toArray list
Parameters:
'T list
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The input list.
Returns: 'T[]
The array containing the elements of the list.
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Builds an array from the given list.
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Views the given list as a sequence.
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Returns the transpose of the given sequence of lists.
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Returns at most N elements in a new list.
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Returns the only element of the list or
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Returns the first element for which the given function returns True. Return None if no such element exists.
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Returns the last element for which the given function returns True. Return None if no such element exists.
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Returns the index of the first element in the list
that satisfies the given predicate.
Return |
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Returns the index of the last element in the list
that satisfies the given predicate.
Return |
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Returns the first element of the list, or
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Tries to find the nth element in the list.
Returns
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Returns the last element of the list.
Return
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Applies the given function to successive elements, returning
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Full Usage:
List.unfold generator state
Parameters:
'State -> ('T * 'State) option
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A function that takes in the current state and returns an option tuple of the next
element of the list and the next state value.
state : 'State
-
The initial state value.
Returns: 'T list
The result list.
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Returns a list that contains the elements generated by the given computation.
The given initial
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Splits a list of pairs into two lists.
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Splits a list of triples into three lists.
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Returns a new list containing only the elements of the list for which the given predicate returns "true"
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Returns a list of sliding windows containing elements drawn from the input list. Each window is returned as a fresh list.
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Combines the two lists into a list of pairs. The two lists must have equal lengths.
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Combines the three lists into a list of triples. The lists must have equal lengths.
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