log

    (PHP 4, PHP 5, PHP 7, PHP 8)

    log — Natural logarithm

    Description

    log(float$num, float$base = M_E): float

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

    Parameters

    num

    The value to calculate the logarithm for

    base

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

    Return Values

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

    See Also

    • log10() - Base-10 logarithm
    • exp() - Calculates the exponent of e
    • pow() - Exponential expression
    • error_log() - Send an error message to the defined error handling routines
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