I was studying the python threading and came across join(). The author told that if thread is in daemon mode then i need to use join() so that thread can finish itself before main thread terminates. but I have also seen him using t.join() even though t was not daemon example code is this i don’t know wh…
Calling a Tornado handler in another handler
I want to split a Tornado handler in two handlers. In the first handler, I want send a command to a sensor. In the second handler, I want to wait for a response from the sensor. Is this possible? Or I can’t call an handler from another? If it’s possible, how I can call this second handler? Thank y…
An easy to understand Web2Py training guide
I am seeking an easy to understand, free, user friendly web2py training resource, that takes the time to introduce each concept and how to use each new object in as much English as possible (and in as little technical jargon as possible). I want a resource that will leave me comfortable and confident to innov…
How to take partial screenshot with Selenium WebDriver in python?
I have searched a lot for this but couldn’t find a solution. Here’s a similar question with a possible solution in java. Is there a similar solution in Python? Answer Other than Selenium, this example also requires the PIL Imaging library. Sometimes this is put in as one of the standard libraries …
Parsing JSON array into class instance objects?
I’m trying to parse some data in Python I have some JSON: If I wanted to parse the “metros” array into and array of Python class Metro objects, how would I setup the class? I was thinking: So I want to go through each metro and put the data into a corresponding Metro object and place that ob…
Parsing boolean values with argparse
I would like to use argparse to parse boolean command-line arguments written as “–foo True” or “–foo False”. For example: However, the following test code does not do what I would like: Sadly, parsed_args.my_bool evaluates to True. This is the case even when I change cmd_li…
What is the difference between chain and chain.from_iterable in itertools?
I could not find any valid example on the internet where I can see the difference between them and why to choose one over the other. Answer The first takes 0 or more arguments, each an iterable, the second one takes one argument which is expected to produce the iterables: but iterables can be any iterator tha…
How to install python library Pyexiv2 and Gexiv2 on osx 10.6.8?
Does anyone knows how to install the python library pyexiv2 and/or Gexiv2 on Mac OSX, ideally on version 10.6.8 and in a virtualenv? Answer It’s pretty simple with Homebrew package manager: If you’re using Macports, it also has exiv2 formulas: http://www.macports.org/ports.php?by=name&substr=e…
How to make a combined set of fields unique in Mongodb in Python
I want to create a table where two of its fields combine to form an index field. My Python code for creating the table is as follows. What I want to do is make the combined fields course_name and group_name unique so that no two groups with the same course_name and group_name can be created. Can someone pleas…
Python libraries to calculate human readable filesize from bytes?
I find hurry.filesize very useful but it doesn’t give output in decimal? For example: But later when I add all the values I don’t get the exact sum. For example if the output of hurry.filesize is in 4 variable and each value is 3. If I add them all, I get output as 15. I am looking for alternative…