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# numpy.format_float_scientific

numpy.format_float_scientific(x, precision=None, unique=True, trim='k', sign=False, pad_left=None, exp_digits=None, min_digits=None)

  Format a floating-point scalar as a decimal string in scientific notation.

  Provides control over rounding, trimming and padding. Uses and assumes IEEE unbiased rounding. Uses the “Dragon4” algorithm.

  Parameters:
    x python float or numpy floating scalar

      Value to format.

    precision non-negative integer or None, optional

      Maximum number of digits to print. May be None if `unique` is True, but must be an integer if unique is False.

    unique boolean, optional

      If True, use a digit-generation strategy which gives the shortest representation which uniquely identifies the floating-point number from other values of the same type, by judicious rounding. If precision is given fewer digits than necessary can be printed. If min_digits is given more can be printed, in which cases the last digit is rounded with unbiased rounding. If False, digits are generated as if printing an infinite-precision value and stopping after precision digits, rounding the remaining value with unbiased rounding

    trim one of ‘k’, ‘.’, ‘0’, ‘-’, optional

      Controls post-processing trimming of trailing digits, as follows:

      - ‘k’ : keep trailing zeros, keep decimal point (no trimming)

      - ‘.’ : trim all trailing zeros, leave decimal point

      - ‘0’ : trim all but the zero before the decimal point. Insert the zero if it is missing.

      - ‘-’ : trim trailing zeros and any trailing decimal point

    sign boolean, optional

      Whether to show the sign for positive values.

    pad_left non-negative integer, optional

      Pad the left side of the string with whitespace until at least that many characters are to the left of the decimal point.

    exp_digits non-negative integer, optional

      Pad the exponent with zeros until it contains at least this many digits. If omitted, the exponent will be at least 2 digits.

    min_digits non-negative integer or None, optional

      Minimum number of digits to print. This only has an effect for unique=True. In that case more digits than necessary to uniquely identify the value may be printed and rounded unbiased.

      New in version 1.21.0.

  Returns:
    rep string

      The string representation of the floating point value

  See also

  `format_float_positional`

  Examples

      >>> import numpy as np
      >>> np.format_float_scientific(np.float32(np.pi))
      '3.1415927e+00'
      >>> s = np.float32(1.23e24)
      >>> np.format_float_scientific(s, unique=False, precision=15)
      '1.230000071797338e+24'
      >>> np.format_float_scientific(s, exp_digits=4)
      '1.23e+0024'