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PHP Manual :: log

log1p || max || Math Functions || PHP Manual

(PHP 4, PHP 5, PHP 7)

logNatural logarithm


float log ( float $arg [, float $base = M_E ] )

If the optional base parameter is specified, log() returns logbase arg, otherwise log() returns the natural logarithm of arg.



The value to calculate the logarithm for


The optional logarithmic base to use (defaults to 'e' and so to the natural logarithm).

Return Values

The logarithm of arg to base, if given, or the natural logarithm.

See Also

  • log10() - Base-10 logarithm
  • exp() - Calculates the exponent of e
  • pow() - Exponential expression

log1p || max || Math Functions || PHP Manual
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