Why isn't it possible to directly convert a floating point number represented as a string in Python to an int variable?
For example,
>>> val=str(10.20)
>>> int(val)
Traceback (most recent call last):
File "<stdin>", line 1, in
ValueError: invalid literal for int() with base 10: '10.2'
However, this works,
>>> int(float(val))
10
The reason is that int is doing two different things in your two examples.
In your first example, int is converting a string to an integer. When you give it 10.2, that is not an integer so it fails.
In your second example, int is casting a floating point value to an integer. This is defined to truncate any fractional part before returning the integer value.
There is a way to do this conversion if you are willing to use a third party library (full disclosure, I am the author). The fastnumbers library was written for quick conversions from string types to number types. One of the conversion functions is fast_forceint, which will convert your string to an integer, even if it has decimals.
>>> from fastnumbers import fast_forceint
>>> fast_forceint('56')
56
>>> fast_forceint('56.0')
56
>>> fast_forceint('56.07')
56
import this). Explicitly converting an integer to a float is very different to quietly dropping parts of a string without warning the user that it wasn't what they expected.