We go by parties. What you get is a warning, which is given by Spyder , probably because it automatically verifies your code against PEP 8 - Style Guide for Python Code which is the official document of coding styles which comments:
Comparisons to singletons like None should always be done with is or
is not, never the equality operators. Also, beware of writing if x
when you really mean if x is not None - e.g. when testing whether to
variable or argument that defaults to None was set to some other
value The other value might have a type (such as a container) that
could be false in a boolean context!
Free translation:
Comparisons between singletons such as "None" should always be made with
"is" or "is not", never with equality operators. Also, have
Be careful when writing "if x" when you really want to say "if not x" -
for example, when you test whether a variable or argument is by default
is "None" has another value. The other value could have a type (for
example, a container) that could be false in a Boolean context!
Your construction if save != False:
is syntactically valid but it is not the "pythonico" style, the recommended way to write this statement would be: if not save:
.
The other problem you have is that you are reusing the same variable ( save
) to save in one case a str
, the directory you mention and otherwise a bool
, the value False
if you do not have said directory. It is not advisable to do so, however if this were the case, the simplest thing is to verify if the data type of save
is a string, in which case we have security that the variable has the directory, for example:
if isinstance(save, str):
print("save tiene el directorio")
But there is a much more elegant way to solve it: first, we must initialize the variable save
as None
, and we must not change the value in case of not having a folder as you are doing now:
save = None
save = "Carpeta" # Proba comentar esta linea
if save is not None:
plt.savefig(save + "/" + title + ".png")
Note: Another way is to initialize save
with a blank string and ask for if save != ""