CODEWITHSUNDEEP
python-3.xstringreplace
DennisZ
DennisZ

Reputation: 113

remove exponents from a formula string

I would like to isolate all operands from a formula (in the form of a string) by taking out the arithmetic operators so take out: "+","-","/","*","**2" the formula string is something like:

"y=A+B1*options+B2*items**2+B3*factor+B4"

However: I can manage for most arithmetic operators, except for the exponents "**2" part. It has to be a wildcard search or so (not positional), because the whole formula might change in future and also might have another exponent (eg **5 or **54)

What would be the easiest way to strip "**?" out of the formula where ? can be any number?

Upvotes: 0

Views: 145

Answers (1)

Hello World
Hello World

Reputation: 76

To match the pattern you want, use the regex string r"\*\*\d+"
Breakdown:

  • r"" is the how one denotes regex in python (see the re module for more info)
  • \* matches a single * character - because the * is a special character in regex, we escape it with the \
  • \d matches a digit
  • + matches the previous pattern at least once greedily: this means it will try to find at least one digit, then keep finding digits until it can find no more. So, it will match **2, **44382, and so on

As for stripping the pattern from the equation, you can do re.sub(pattern, "", equation) - replacing all instances of the pattern with nothing

Upvotes: 1

Related Questions