是否可以更改内置haskell范围函数或文字的步长？

默认

[1..5]

给出这个

[1,2,3,4,5]

也可以使用范围功能完成.是否可以更改点之间的步长,以便我可以得到类似下面的内容？

[1,1.5,2,2.5,3,3.5,4,4.5,5] 

Johannes Wei.. 21

[1,1.5..5]

Paul Johnson.. 18

你必须小心浮点运算.它不能精确地代表1.1,所以如果你试试

Prelude> [0,0.1 .. 1]
[0.0,0.1,0.2,0.30000000000000004,0.4,0.5,0.6,0.7,0.7999999999999999,0.8999999999999999,0.9999999999999999]

最好的方式更像是:

Prelude> map (/10) [0..10]
[0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0]

mattiast.. 6

实际上,[1..5]是语法糖

enumFromTo 1 5 

并[1,1.5..5]为

enumFromThenTo 1 1.5 5

有关更多信息,请参阅http://en.wikibooks.org/wiki/Haskell/Syntactic_sugar

[1,1.5..5]

你必须小心浮点运算.它不能精确地代表1.1,所以如果你试试

Prelude> [0,0.1 .. 1]
[0.0,0.1,0.2,0.30000000000000004,0.4,0.5,0.6,0.7,0.7999999999999999,0.8999999999999999,0.9999999999999999]

最好的方式更像是:

Prelude> map (/10) [0..10]
[0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0]

实际上,[1..5]是语法糖

enumFromTo 1 5 

并[1,1.5..5]为

enumFromThenTo 1 1.5 5

有关更多信息,请参阅http://en.wikibooks.org/wiki/Haskell/Syntactic_sugar