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Tag: python

Prepend line to beginning of a file

I can do this using a separate file, but how do I append a line to the beginning of a file? This starts writing from the end of the file since the file is opened in append mode. Answer In modes ‘a’ or ‘a+’, any writing is done at the end of the file, even if at the current moment

Django DateTimeField auto_now_add not working

In one of the model i have set one timestamp field as follows: While in shell i am able to create a obj and save it, however in my application it is raising a exception that created_datetime field cannot be null. Confused where things went wrong!! How to reslove it. Answer You can do something like this

Joining pairs of elements of a list

I know that a list can be joined to make one long string as in: Obviously this would output: However, what I am trying to do is simply join the first and second strings in the list, then join the third and fourth and so on. In short, from the above example instead achieve an output of: Is there any

Generating PDFs from SVG input

I am trying to generate a PDF from a SVG input file with Python in a Django application. I have already found 2 working solutions: cairo+rsvg and imagemagick but they both have one problem: They have …

Print Javascript Exceptions In A QWebView To The Console

I’m using PyQt4 and a QWebView widget to view a webpage, but it appears as though there is a problem with my Javascript. Other browsers seem to run ok, so I would like to know if any exceptions are occurring by printing them to the console. The code I’m using is below. What do I need to add to do

List sorting/modify problem

Initially, I wasn’t sure whether this was the appropriate place for this question, but after reading through the FAQ I feel fairly confident the topic is acceptable…. Furthermore I wasn’t sure if this would be classified as a particular type of problem (eg. a knapsack problem), thus, the title is rather vague. I’m sorry for […]