I noticed that if I type, for instance >>> a: 5 as input of the python interpreter, it does not return an error (whether or not the variable 'a' is already defined). However, if I type >>> a afterwards, I get the usual NameError.
My question is: what does the python interpreter do when I type this kind of dictionary syntax without the curly braces?
Originally, I found this syntax in matplotlib's matplotlibrc file (see here).
It defines a type hint. But without a value, the variable will not be initialized in the global scope.
>>> a: int = 3
>>> globals()['__annotations__']
{'a': <class 'int'>}
>>> a
3
>>> b: str
>>> globals()['__annotations__']
{'a': <class 'int'>, 'b': <class 'str'>}
>>> b
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'b' is not defined
a: 5 in the interpreter uses the type hint syntax, but this has nothing to do with what you see in matplotlib's documentation that defines a configuration file (and thus is not python code).
from the documentation:
You can create custom styles and use them by calling style.use with the path or URL to the style sheet.
For example, you might want to create ./images/presentation.mplstyle with the following:
axes.titlesize : 24
axes.labelsize : 20
lines.linewidth : 3
lines.markersize : 10
xtick.labelsize : 16
ytick.labelsize : 16
The above is not python code
