interpreter

Current assignment needs me to write a program to read a file with instructions in a very tiny and basic programming language (behaves a little like FORTRAN) and execute those instructions. Basically it's a simple interpreter for the language I guess. It's completely linear, with statements all being defined in sequence and it only has String and integer variables. There are 8 keywords and 4 arithmetic operators I would need to find and define if they exist within the source file, and each line must start off with one of the reserved words. A program in this language might look something like

I have read the following posts but I am still unsure of something. Python Compilation/Interpretation Process Why python compile the source to bytecode before interpreting? If I have a single Python file myfunctions.py containing the following code. x = 3 def f(): print x x = 2 Then, saying $ python myfunctions.py runs perfectly fine. But now make one small change to the above file. The new file looks as shown below. x = 3 def f(): print x x = 2 f() # there is a function call now This time, the code gives out an error. Now, I am trying to understand this behavior. And so far, these are my

I just found something weird in the Python interpreter. Let me show you: $ python Python 2.7.1+ (r271:86832, Apr 11 2011, 18:13:53) [GCC 4.5.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> _ Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name '_' is not defined >>> 5 + 4 9 >>> _ 9 >>> 'Hello world' 'Hello world' >>> _ 'Hello world' >>> type(3.5) <type 'float'> >>> _ <type 'float'> You can try this in your interpreter; there are no tricks at work here! Is the result of the last executed line being assigned to a variable

Say I have a variable containing bytes: >>> a = b'Hello World' It can be verified with: >>> type(a) <class 'bytes'> Now I try and convert a into a string with str() : >>> b = str(a) and sure enough it is a string: >>> type(b) <class 'str'> Now I try and print b but I get a totally unexpected result: >>> print(b) b'Hello World' It returns a string, as I would expect but also it keeps the b (byte symbol) and the ' (quotation marks). Why does it do this, and not just print the message between the quotation marks? Don't think of a bytes value as a string in some default 8-bit encoding. It's just

Say I run a Python (2.7, though I'm not sure that makes a difference here) script. Instead of terminating the script, I tab out, or somehow switch back to my editing environment. I can then modify the script and save it, but this changes nothing in the still-running script. Does Python load all source files into memory completely at launch? I am under the impression that this is how the Python interpreter works, but this contradicts my other views of the Python interpreter: I have heard that .pyc files serve as byte-code for Python's virtual machine, like .class files in Java. At the same time

This question already has an answer here: Find full path of the Python interpreter? 3 answers I have several software packages that install various installs of Python. For example: C:\Python27\ArcGIS10.1 C:\Python27\ArcGIS10.2 C:\Python27|ArcGISx6410.1 Using sys.version does not work for my case since I need to know where the actual install is located, not the version. How can I determine which install my Python interpreter is using? kindall What you want is sys.executable , which will give the path to actual interpreter executable. 来源： https://stackoverflow.com/questions/24895901/how-to