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Galaxy Being

17 Feb 2021 17 Feb '21

12:13 p.m.

I'm trying to use Decimal but (I'm guessing) I don't know how to import it. import Data.Decimal dList :: [Decimal] dList = [1.1,1.2..2.0] : <interactive>:70:11-17: error: : Not in scope: type constructor or class `Decimal' Obviously I was asleep the day the teacher told us how to do this. . . . LB

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Francesco Ariis

17 Feb 17 Feb

1:57 p.m.

Il 17 febbraio 2021 alle 11:13 Galaxy Being ha scritto:

I'm trying to use Decimal but (I'm guessing) I don't know how to import it.

import Data.Decimal

dList :: [Decimal] dList = [1.1,1.2..2.0]

: <interactive>:70:11-17: error: : Not in scope: type constructor or class `Decimal'

Works here. You need to add `Decimal` the dependencies of your project or install it globally first —F

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Galaxy Being

3:17 p.m.

How would I install it globally? I'm not using projects, I'm just at the ghci REPL. On Wed, Feb 17, 2021 at 12:57 PM Francesco Ariis wrote:

Il 17 febbraio 2021 alle 11:13 Galaxy Being ha scritto:

...
I'm trying to use Decimal but (I'm guessing) I don't know how to import it.

import Data.Decimal

dList :: [Decimal] dList = [1.1,1.2..2.0]

: <interactive>:70:11-17: error: : Not in scope: type constructor or class `Decimal'

Works here. You need to add `Decimal` the dependencies of your project or install it globally first —F _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

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Francesco Ariis

3:42 p.m.

Il 17 febbraio 2021 alle 14:17 Galaxy Being ha scritto:

How would I install it globally? I'm not using projects, I'm just at the ghci REPL.

Most likely cabal install --lib Decimal Check what Tom has said too —F

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Galaxy Being

8:26 p.m.

I'm trying to create a list of real numbers with a two-decimal interval, a la

[1.0,1.01,1.02,...1.99,2.00]

however, I get the float approximation problem [1.0,1.01,1.02,1.03,1.04,1.05,1.06,1.07,1.08,1.09,1.1,1.11,1.12,1.1300000000000001,1.1400000000000001,... So I attempted to compensate with import Data.Decimal map (roundTo 2) [1.00,1.01..2.0] I don't have to do it this way if there is another rounding function to correct the float overrun issue. On Wed, Feb 17, 2021 at 2:43 PM Francesco Ariis wrote:

Il 17 febbraio 2021 alle 14:17 Galaxy Being ha scritto:

...
How would I install it globally? I'm not using projects, I'm just at the ghci REPL.

Most likely

cabal install --lib Decimal

Check what Tom has said too —F _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

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Bob Ippolito

9:36 p.m.

You don't need to do any rounding if the list is already Decimal. If you wanted to format a Double with some specific decimal representation you could look at Numeric.showFFloatAlt or similar. import Data.Decimal dList :: [Decimal] dList = [1.00,1.01..2.00] main = print dList On Wed, Feb 17, 2021 at 5:27 PM Galaxy Being wrote:

I'm trying to create a list of real numbers with a two-decimal interval, a la

...
[1.0,1.01,1.02,...1.99,2.00]

however, I get the float approximation problem

[1.0,1.01,1.02,1.03,1.04,1.05,1.06,1.07,1.08,1.09,1.1,1.11,1.12,1.1300000000000001,1.1400000000000001,...

So I attempted to compensate with

import Data.Decimal map (roundTo 2) [1.00,1.01..2.0]

I don't have to do it this way if there is another rounding function to correct the float overrun issue.

On Wed, Feb 17, 2021 at 2:43 PM Francesco Ariis wrote:

...
Il 17 febbraio 2021 alle 14:17 Galaxy Being ha scritto:

...
How would I install it globally? I'm not using projects, I'm just at the ghci REPL.

Most likely

cabal install --lib Decimal

Check what Tom has said too —F _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

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Galaxy Being

10:42 p.m.

As I've said, working at the ghci REPL, import Data.Decimal dList :: [Decimal] dList = [1.00,1.01..2.00] main = print dList errors out : <interactive>:76:11-17: error: : Not in scope: type constructor or class `Decimal' On Wed, Feb 17, 2021 at 8:37 PM Bob Ippolito wrote:

You don't need to do any rounding if the list is already Decimal.

If you wanted to format a Double with some specific decimal representation you could look at Numeric.showFFloatAlt or similar.

import Data.Decimal

dList :: [Decimal] dList = [1.00,1.01..2.00]

main = print dList

On Wed, Feb 17, 2021 at 5:27 PM Galaxy Being wrote:

...
I'm trying to create a list of real numbers with a two-decimal interval, a la

...
[1.0,1.01,1.02,...1.99,2.00]

however, I get the float approximation problem

[1.0,1.01,1.02,1.03,1.04,1.05,1.06,1.07,1.08,1.09,1.1,1.11,1.12,1.1300000000000001,1.1400000000000001,...

So I attempted to compensate with

import Data.Decimal map (roundTo 2) [1.00,1.01..2.0]

I don't have to do it this way if there is another rounding function to correct the float overrun issue.

On Wed, Feb 17, 2021 at 2:43 PM Francesco Ariis wrote:

...
...
How would I install it globally? I'm not using projects, I'm just at

Il 17 febbraio 2021 alle 14:17 Galaxy Being ha scritto: the

...
ghci REPL.

Most likely

cabal install --lib Decimal

Check what Tom has said too —F _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

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Bob Ippolito

11:29 p.m.

Like others said, you'll need to install the Decimal package in order to use Data.Decimal. If you really wanted to do it with a floating point type and no dependencies you can use showFFloatAlt from Numeric to display with a specified precision. import Numeric import Text.Show main = putStrLn . showListWith (showFFloatAlt (Just 2)) [1.00, 1.01 .. 2.00] $ "" On Wed, Feb 17, 2021 at 7:42 PM Galaxy Being wrote:

As I've said, working at the ghci REPL,

import Data.Decimal dList :: [Decimal] dList = [1.00,1.01..2.00] main = print dList

errors out

: <interactive>:76:11-17: error: : Not in scope: type constructor or class `Decimal'

On Wed, Feb 17, 2021 at 8:37 PM Bob Ippolito wrote:

...
You don't need to do any rounding if the list is already Decimal.

If you wanted to format a Double with some specific decimal representation you could look at Numeric.showFFloatAlt or similar.

import Data.Decimal

dList :: [Decimal] dList = [1.00,1.01..2.00]

main = print dList

On Wed, Feb 17, 2021 at 5:27 PM Galaxy Being wrote:

...
I'm trying to create a list of real numbers with a two-decimal interval, a la

...
[1.0,1.01,1.02,...1.99,2.00]

however, I get the float approximation problem

[1.0,1.01,1.02,1.03,1.04,1.05,1.06,1.07,1.08,1.09,1.1,1.11,1.12,1.1300000000000001,1.1400000000000001,...

So I attempted to compensate with

import Data.Decimal map (roundTo 2) [1.00,1.01..2.0]

I don't have to do it this way if there is another rounding function to correct the float overrun issue.

On Wed, Feb 17, 2021 at 2:43 PM Francesco Ariis wrote:

...
...
How would I install it globally? I'm not using projects, I'm just at

Il 17 febbraio 2021 alle 14:17 Galaxy Being ha scritto: the

...
ghci REPL.

Most likely

cabal install --lib Decimal

Check what Tom has said too —F _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

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Daniel Trstenjak

18 Feb 18 Feb

2:32 a.m.

On Wed, Feb 17, 2021 at 02:17:32PM -0600, Galaxy Being wrote:

How would I install it globally? I'm not using projects, I'm just at the ghci REPL.

Even for such small tests it's simpler to just use a cabal project: mkdir decimal-test cd decimal-test cabal init -p decimal-test -d base -d Decimal cabal repl If you need further dependencies you can then extend the 'build-depends' list in the file 'decimal-test.cabal'. Greetings, Daniel

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amindfv＠mailbox.org

17 Feb 17 Feb

2:58 p.m.

Is it possible you mean to use Double or Float instead of Decimal? Tom On Wed, Feb 17, 2021 at 11:13:19AM -0600, Galaxy Being wrote:

I'm trying to use Decimal but (I'm guessing) I don't know how to import it.

import Data.Decimal

dList :: [Decimal] dList = [1.1,1.2..2.0]

: <interactive>:70:11-17: error: : Not in scope: type constructor or class `Decimal'

Obviously I was asleep the day the teacher told us how to do this. . . .

LB

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

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amindfv＠mailbox.org
Bob Ippolito
Daniel Trstenjak
Francesco Ariis
Galaxy Being