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I want to truncate a simple number to n decimal digits. For example, 2/3. I used
f[x_, n_] := N[IntegerPart[x 10^n]/10^n]
but I get
f[2/3, 20] = 0.666667
Is there a way to get
f[2/3, 20] = 0.66666666666666666666 ?
I have searched a lot but I haven't really found an answer. I am looking for something like N or Round for truncation.
ClearAll[f]
f[x_, n_] :=
Module[{s = RealDigits[x, 10, n + IntegerLength@IntegerPart[x]]},
N[FromDigits[s[[1]]]/10^(n), n + s[[2]]]];
f[2/3, 20]
0.66666666666666666666
Trunc[x_, n_] := N[FromDigits[RealDigits[x, 10, n]], n] also works.
n decimal digits like f[5000/3, 20]=1666.66666666666666666666. thanx for accepting
$\endgroup$
– J42161217
Nov 27 '18 at 12:43
N[2/3, 20]$\endgroup$ – J42161217 Nov 27 '18 at 12:10Nrounds the last decimal digit. I getN[2/3, 20] = 0.66666666666666666667$\endgroup$ – Alex Nov 27 '18 at 12:12RealDigits[2/3, 10, 20]$\endgroup$ – Carl Lange Nov 27 '18 at 12:18NumberForm[N[2/3], 30]stops after 15 to 16 decimals but does not round up. $\endgroup$ – Titus Nov 27 '18 at 12:37