scientific notation with superscript exponent

2018-11-30

An answer to this question on Stack Overflow.

Question

I'm attempting to format numbers in scientific notation with exponents of base 10, e.g. write 0.00123 as 1.23x10^–3, using python 3.

I found this great function which prints 1.23x10^-3, but how can the caret-exponent be replaced with a superscript?

def sci_notation(number, sig_fig=2):
    ret_string = "{0:.{1:d}e}".format(number, sig_fig)
    a,b = ret_string.split("e")
    b = int(b)         # removed leading "+" and strips leading zeros too.
    return a + "x10^" + str(b)
print(sci_notation(0.001234, sig_fig=2))      # Outputs 1.23x10^-3

The function is modified from https://stackoverflow.com/a/29261252/8542513.

I've attempted to incorporate the answer from https://stackoverflow.com/a/8651690/8542513 to format the superscript, but I'm not sure how sympy works with variables:

from sympy import pretty_print as pp, latex
from sympy.abc import a, b, n
def sci_notation(number, sig_fig=2):
  ret_string = "{0:.{1:d}e}".format(number, sig_fig)
  a,b = ret_string.split("e")
  b = int(b)             #removed leading "+" and strips leading zeros too.
  b = str(b)
  expr = a + "x10"**b    #Here's my problem
  pp(expr)               # default
  pp(expr, use_unicode=True)
  return latex(expr)
print(latex(sci_notation(0.001234, sig_fig=2)))

This returns: TypeError: unsupported operand type(s) for ** or pow(): 'str' and 'int'

Answer

Here's a simple solution:

def SuperScriptinate(number):
  return number.replace('0','⁰').replace('1','¹').replace('2','²').replace('3','³').replace('4','⁴').replace('5','⁵').replace('6','⁶').replace('7','⁷').replace('8','⁸').replace('9','⁹').replace('-','⁻')
def sci_notation(number, sig_fig=2):
    ret_string = "{0:.{1:d}e}".format(number, sig_fig)
    a,b = ret_string.split("e")
    b = int(b)         # removed leading "+" and strips leading zeros too.
    return a + "x10^" + SuperScriptinate(str(b))