# Wolfram Language & System 11.0 (2016)|Legacy Documentation

This is documentation for an earlier version of the Wolfram Language.
BUILT-IN WOLFRAM LANGUAGE SYMBOL

# FromDigits

FromDigits[list]
constructs an integer from the list of its decimal digits.

FromDigits[list,b]
takes the digits to be given in base b.

uses the mixed radix with list of bases blist.

FromDigits["string"]
constructs an integer from a string of digits.

FromDigits["string","Roman"]
constructs an integer from Roman numerals.

## DetailsDetails

• FromDigits is effectively the inverse of IntegerDigits and IntegerString.
• FromDigits[{list,n},b] takes n to be an exponent, while FromDigits[{{a1,a2,,{rep}},n},b] takes rep to be repeated, so that FromDigits can also be used as the inverse of RealDigits.
• Since discards the sign of n, is Abs[n], not just n. »
• The digits in list and the base b need not be positive integers, and can be any expression. »
• If Indeterminate appears in list, it is assumed to signify unknown digits beyond the precision of an approximate real number. »
• FromDigits["string",b] takes the digits in "string" to be given in base b.
• In FromDigits["string",b], digits above 9 can be represented by letters az or AZ.

## ExamplesExamplesopen allclose all

### Basic Examples  (5)Basic Examples  (5)

Construct a number from its base-10 digits:

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Base-2 digits:

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Construct a number from digits given as string:

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Construct a number from digits base 2:

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Construct a number from digits in a mixed radix system:

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