Q言語-組み込み関数
ザ・ qプログラミング言語には、豊富で強力な組み込み関数のセットがあります。組み込み関数には、次のタイプがあります。
String function −文字列を入力として受け取り、文字列を返します。
Aggregate function −リストを入力として受け取り、アトムを返します。
Uniform function −リストを取得し、同じカウントのリストを返します。
Mathematical function −数値引数を取り、数値引数を返します。
Miscellaneous function −上記以外のすべての機能。
文字列関数
のように-パターンマッチング
q)/like is a dyadic, performs pattern matching, return 1b on success else 0b
q)"John" like "J??n"
1b
q)"John My Name" like "J*"
1bltrim-先頭の空白を削除します
q)/ ltrim - monadic ltrim takes string argument, removes leading blanks
q)ltrim " Rick "
"Rick "rtrim-末尾の空白を削除します
q)/rtrim - takes string argument, returns the result of removing trailing blanks
q)rtrim " Rick "
" Rick"ss-文字列検索
q)/ss - string search, perform pattern matching, same as "like" but return the indices of the matches of the pattern in source.
q)"Life is beautiful" ss "i"
1 5 13トリム-先頭と末尾の空白を削除します
q)/trim - takes string argument, returns the result of removing leading & trailing blanks
q)trim " John "
"John"数学関数
acos-cosの逆数
q)/acos - inverse of cos, for input between -1 and 1, return float between 0 and pi
q)acos 1
0f
q)acos -1
3.141593
q)acos 0
1.570796cor −は相関関係を与えます
q)/cor - the dyadic takes two numeric lists of same count, returns a correlation between the items of the two arguments
q)27 18 18 9 0 cor 27 36 45 54 63
-0.9707253クロス-デカルト積
q)/cross - takes atoms or lists as arguments and returns their Cartesian product
q)9 18 cross `x`y`z
9 `x
9 `y
9 `z
18 `x
18 `y
18 `zvar −分散
q)/var - monadic, takes a scaler or numeric list and returns a float equal to the mathematical variance of the items
q)var 45
0f
q)var 9 18 27 36
101.25wavg
q)/wavg - dyadic, takes two numeric lists of the same count and returns the average of the second argument weighted by the first argument.
q)1 2 3 4 wavg 200 300 400 500
400f集計関数
すべて-＆操作
q)/all - monadic, takes a scaler or list of numeric type and returns the result of & applied across the items.
q)all 0b
0b
q)all 9 18 27 36
1b
q)all 10 20 30
1b任意-| 操作
q)/any - monadic, takes scaler or list of numeric type and the return the result of | applied across the items
q)any 20 30 40 50
1b
q)any 20012.02.12 2013.03.11
'20012.02.12prd-算術積
q)/prd - monadic, takes scaler, list, dictionary or table of numeric type and returns the arithmetic product.
q)prd `x`y`z! 10 20 30
6000
q)prd ((1 2; 3 4);(10 20; 30 40))
10 40
90 160合計-算術合計
q)/sum - monadic, takes a scaler, list,dictionary or table of numeric type and returns the arithmetic sum.
q)sum 2 3 4 5 6
20
q)sum (1 2; 4 5)
5 7統一された機能
デルタ-前のアイテムとの違い。
q)/deltas -takes a scalar, list, dictionary or table and returns the difference of each item from its predecessor.
q)deltas 2 3 5 7 9
2 1 2 2 2
q)deltas `x`y`z!9 18 27
x | 9
y | 9
z | 9塗りつぶし-null値を塗りつぶします
q)/fills - takes scalar, list, dictionary or table of numeric type and returns a c copy of the source in which non-null items are propagated forward to fill nulls
q)fills 1 0N 2 0N 4
1 1 2 2 4
q)fills `a`b`c`d! 10 0N 30 0N
a | 10
b | 10
c | 30
d | 30maxs-累積最大値
q)/maxs - takes scalar, list, dictionary or table and returns the cumulative maximum of the source items.
q)maxs 1 2 4 3 9 13 2
1 2 4 4 9 13 13
q)maxs `a`b`c`d!9 18 0 36
a | 9
b | 18
c | 18
d | 36その他の機能
カウント-要素の戻り数
q)/count - returns the number of entities in its argument.
q)count 10 30 30
3
q)count (til 9)
9
q)count ([]a:9 18 27;b:1.1 2.2 3.3)
3Distinct-異なるエンティティを返します
q)/distinct - monadic, returns the distinct entities in its argument
q)distinct 1 2 3 4 2 3 4 5 6 9
1 2 3 4 5 6 9ただし、2番目の引数に要素が存在しません。
q)/except - takes a simple list (target) as its first argument and returns a list containing the items of target that are not in its second argument
q)1 2 3 4 3 1 except 1
2 3 4 3fill-最初の引数でnullを埋める
q)/fill (^) - takes an atom as its first argument and a list(target) as its second argument and return a list obtained by substituting the first argument for every occurrence of null in target
q)42^ 9 18 0N 27 0N 36
9 18 42 27 42 36
q)";"^"Life is Beautiful"
"Life;is;Beautiful"