Python 3: UnboundLocalError: local variable referenced before assignment
The following code gives the error UnboundLocalError: local variable ‘Var1’ referenced before assignment: How can I fix this? Thanks for any help!
python-3.x
Dice rolling simulator in Python
Let’s walk through the process: You already know what you need to generate random numbers. import random (or you could be more specific and say from random import randint, because we only need randint in this program) As you’ve already said it; print(“You rolled”,random.randint(1,6)) “rolls the dice”. but it does it only once, so you need a loop to repeat it. … Read more
How do you use subprocess.check_output() in Python?
The right answer (using Python 2.7 and later, since check_output() was introduced then) is: To demonstrate, here are my two programs: py2.py: py3.py: Running it: Here’s what’s wrong with each of your versions: First, str(‘python py2.py’) is exactly the same thing as ‘python py2.py’—you’re taking a str, and calling str to convert it to an str. This makes the code harder to read, longer, … Read more
PermissionError: [WinError 5] Access is denied
Everytime I try to delete a file using os.remove() in Python 3.5.1, I get this message PermissionError: [WinError 5] Access is denied And here is that simple code: Didn’t even delete a single file in the directory or sub-directory.
Python: create a pandas data frame from a list
DataFrame.from_records treats string as a character list. so it needs as many columns as length of string. You could simply use the DataFrame constructor.
How to use sys.exit() in Python
I think you can use You may check it here in the python 2.7 doc: The optional argument arg can be an integer giving the exit status (defaulting to zero), or another type of object. If it is an integer, zero is considered “successful termination” and any nonzero value is considered “abnormal termination” by shells and the … Read more
Series Summation using for loop in python
Python syntax is a bit different than c. In particular, we usually use the range function to create the values for the iterator variable (this is what was in Stephen Rauch’s comment). The first argument to range is the starting value, the second is the final value (non-inclusive), and the third value is the step size (default of 1). … Read more
‘dict’ object has no attribute ‘has_key’
has_key was removed in Python 3. From the documentation: Removed dict.has_key() – use the in operator instead. Here’s an example:
What does -> mean in Python function definitions?
It’s a function annotation. In more detail, Python 2.x has docstrings, which allow you to attach a metadata string to various types of object. This is amazingly handy, so Python 3 extends the feature by allowing you to attach metadata to functions describing their parameters and return values. There’s no preconceived use case, but the PEP … Read more
What is the Python 3 equivalent of “python -m SimpleHTTPServer”
From the docs: The SimpleHTTPServer module has been merged into http.server in Python 3.0. The 2to3 tool will automatically adapt imports when converting your sources to 3.0. So, your command is python -m http.server, or depending on your installation, it can be: