There are many free tools available to help people manage their stock portfolio. For example, you can use Yahoo! Finance to track your current holdings. For each stock it list many detail financial data as well as stock chart for various periods. Still, when you need to do more sophisticated analysis, there is nothing that beats the power of spreadsheet.

Fortunately it is easy to pull the data from the web tool to a spreadsheet. You can simple copy and paste the data into a spreadsheet to get a properly formatted table. For there you can add your custom formula or charts. The problem is unlike the web view, data downloaded on a spreadsheet is not updated with current market information. On the other hand if you download the again you will lose all custom formula you have added.

To get the best of both world, I have created a script to so that you can update your spreadsheet with the latest stock quote from the web. This is a simple Python script. It first looks for the stock symbols in your portfolio in your spreadsheet. It then fetches the (15 minute delayed) stock quote from a Yahoo web services. Finally it updates the cells in the spreadsheet with new data from Yahoo.

This tool requires Python 2.5, Excel and pywin32 extension. Click here to download the stock quote update script.

2008.06.22 [python] - comments

Recently I have come to aware of the issue of Great Pacific Garbage Patch from the media. It is large region in the Pacific Ocean that has accumulated much man-made garbage carried there by ocean current. Amount them are many plastic trash. On one hand plastic are very durable because they are not biodegradable. On the other hand plastic are photodegradable, meaning under the exposure of sunlight, they will slowly break down into smaller and smaller pieces. The result is a high concentration of pollutant in the water that is nearly impossible to clean up.

To most people this problem is nothing more than just a scientific interest. After all we don't venture into the middle of the ocean. So this problem is out of sight, out of mind. But today I have personally experienced the effect of photodegradation right in my own backyard.

Two years ago my mother has spent several months in my home. In her spare time she has built a vegetable garden in the yard. Being, shall I say, a resourceful person, she has reused many trash items to build a trellis. For example she scavenged many plastic bags that we would have throw away and used it as ties to the stakes.

Unfortunately, after she has left, we have not given the garden proper upkeep. It was quickly overrun by weeds. And finally I have to clear it out. As I was dismantling the trellis, I found the plastic bags have become very flaky. After exposed in sunlight for 2 years, the have all photodegraded. As I tried to remove them, they just break down into small pieces of white plastic and scattered all over the garden. There is just no way for me to mop up these tiny pieces from the soil. Who would have thought plastic bags can turn into a much bigger headache after it has degraded like this.

2008.06.14 comments