In Ex13 (LP3THW), the first line is “from sys import argv”, so (I think), the program is asking the interpreter to import the argv function/class/whatever from the sys module/library/whatever. In Ex23, the line is just “import sys”. Does this import the entire sys module, with all included functions/classes/whatevers? In Ex35, it’s back to importing just one function: “from sys import exit”. Now, in looking things up online, I’ve found code examples that include similar lines, as well as “from sys import *”. I’m pretty sure, though I can’t find it now, I’ve also seen “from sys import *” on line 1, and "from sys import " on line 2, or something similar.
So, when should you import a single function, when should you import the whole library, and when should you - apparently? - do both? Is “from sys import " the same as “import sys”, or is "” actually an individual function, similar to “argv”? (I’ve been assuming it’s just a wildcard.)