RealDigits
 Usage
• RealDigits[x] 给出近似实数x中的数字构成的阵列,和小数点左边的数位个数.
• RealDigits[x, b]给出x中一列以b为基底的数字.
• RealDigits[x, b, len] 给出 len 个数位的列表.
• RealDigits[x, b, len, n] 给出以  的系数开始的 len个数位.
Notes
• RealDigits[x] 通常返回一个长度等于Precision[x]的数字列表. • RealDigits[x] 和 RealDigits[x, b] 通常要求 x 是一个由,举例来讲,N返回的近似实数. RealDigits[x, b, len] 也适用于精确数. • 对于一个精确的有理数, RealDigits[x]返回一个形如   ,  , ... ,   ,  , ...   的数字列表,表示数字  被  的无限循环跟随. • 如果 len 大于 Log[10, b] Precision[x]剩下的数字以Indeterminate填充. • RealDigits[x, b, len, n] 以  的系数开始，并在必要时用0截断或填充. • RealDigits[x, b, len, -1] 以x中紧挨以b为基底的小数点右边的数字开始. • RealDigits[x, b]中的基底 b不必是整数.对使得  的任意实数 b , RealDigits[x, b]连续找到 b的幂的最大整数倍使得当得到一个非负余项时可以被去掉. • RealDigits[x] 不考虑 x 的符号. • FromDigits可以被用作RealDigits的逆.
 Further Examples
Here is an approximation to  .
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This gives the individual digits as a list. The  at the end means that there are  digits to the left of the decimal point.
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As an exact fraction,  has a repeating part.
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Here is an approximate number.
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Here are its digits. The  at the end means that there are  digits to the left of the decimal point.
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RealDigits returns a list of digits whose length is equal to the number's precision.
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Similarly, these are its digits in base  . There are  digits in all.
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 digits in base  is  digits in base  .
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Here is an exact number.
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This shows the first  digits of n in base  .The total number of digits is  .
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This gives the first  digits starting with the coefficient of  . There are  digits counting from that coefficient.
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