Lets say we have a small Python dictionary called fruit that looks like this: fruit = {‘a’:’apple’, ‘b’:’banana’, ‘c’:’cherry’} The most common way to get a value is to retrieve it by its key, using this special syntax: name_of_dictionary[ name_of_key ] By using the name of the key in brackets after the name of the … Continue reading Python: How to use the dictionary get( ) method
Python Language
Python: How to use List Comprehensions
List Comprehensions were introduced to the Python language in PEP-202 to provide a more concise syntactical way to produce lists where map(), filter(), for loops, and if statements would normally be used. A list comprehension can be summed up like this: new_list = [item action for item in existing_list with optional if condition] This is … Continue reading Python: How to use List Comprehensions
Python: How to use the built-in help( ) and dir( ) functions
In addition to the .__doc__ function which is useful for seeing the docstring of a function or class object, Python has a couple of other useful built-in help functions called help() and dir(). The help() function can be used to inspect functions. For example: >>> help(docstring_test) Help on function docstring_test in module __main__: docstring_test() This … Continue reading Python: How to use the built-in help( ) and dir( ) functions
Python: How to set and read Docstrings
Docstrings are a triple quoted string that you declare at the beginning of object definitions such as functions, classes, and class methods. They are used to describe the purpose of the function, as a brief summary, but not describe how the function works. To describe how a function works, you would use regular comments. A … Continue reading Python: How to set and read Docstrings
Python on the web: How to delete cookies in a CGI script
After you have a cookie that has been set, here is how you can delete it. The trick is to send an update to the cookie where you feed it an expiration date that is already in the past. For example: print “Set-Cookie: xml_edit_tool=Value of cookie; ‘expires=Wed, 28 Aug 2013 18:30:00 GMT’ \r\n” Note: When … Continue reading Python on the web: How to delete cookies in a CGI script
Python on the web: How to update cookies in a CGI script
Once you’ve retrieved a cookie via a function that returns the cookie as a dictionary of key value pairs, you can update the cookie in nearly the same way that you originally set the cookie. The only difference is that this time you can set different values. In this example, I am passing the retrieved … Continue reading Python on the web: How to update cookies in a CGI script
Python on the web: How to get cookies in a CGI script
In this previous article I detailed how to set cookies in a CGI script: Python on the web: How to set cookies in a CGI script In this article I am going to describe how to get those cookies in a CGI script. Get ‘HTTP_COOKIE’ from the Environment variables. Account for the fact that this … Continue reading Python on the web: How to get cookies in a CGI script
Python on the web: How to get a CGI script to recognize two submit buttons with separate values in one form
In one of my Python cgi scripts I have a web form with some hidden values, text fields, and two submit buttons. I want my cgi script to do something different depending on which submit button was clicked. One of the submit buttons is for completing a review without making any changes and is called … Continue reading Python on the web: How to get a CGI script to recognize two submit buttons with separate values in one form
Python on the web: How to set cookies in a CGI script
I am working on a Python CGI web tool that allows a user to traverse through a long list of xml elements, where each element appears on the screen one at a time. The tool allows the user to make changes to editable fields and creates a report of the deltas, as well as a … Continue reading Python on the web: How to set cookies in a CGI script
Python on the web: How to use Environment variables to detect script path
If you are writing Python scripts to run from the cgi-bin of your website, here is some code that will allow the script to detect it’s own path, so that it doesn’t have to be hard coded. The preferable way is to use the environment variable ‘SCRIPT_URI’. For example: this_script = os.environ[‘script_uri’] Note: Depending on … Continue reading Python on the web: How to use Environment variables to detect script path