How do I convert a string to a double in Python?

>>> x = "2342.34"
>>> float(x)
2342.3400000000001

There you go. Use float (which behaves like and has the same precision as a C,C++, or Java double).

Be aware that if your string number contains more than 15 significant digits float(s) will round it.In those cases it is better to use Decimal

Here is an explanation and some code samples: https://docs.python.org/3/library/sys.html#sys.float_info