1. Python Programming Challenge
Jeffery S. Horsburgh
Hydroinformatics
Fall 2016
This work was funded by National Science Foundation Grants EPS and EPS

2. Objectives Introduction to the Python programming language
Write and execute computer code to automate repetitive tasks
Discover and access data from major data sources
Retrieve and use data from common hydrologic data sources

3. Coding Challenge

4. Get the Data

5. Coding Challenge
Choose a real-time streamflow gage from the USGS that you are interested in. It could be a nearby gage or one that is near and dear to your heart. To see an interactive map of gage locations, go to:
Create a Python script that does the following:
Download the most recent data from the USGS website
Read the file
Extract the most recent streamflow value from the file
Print the most recent streamflow value and the date at which it occurred to the screen

6. Example Solution
“The most recent streamflow value for USGS Gage was 109 cfs on :15.”

7. Step 1: Create a New PyCharm Project
Open PyCharm
Select File  New Project
Name your project and select the interpreter

8. Step 2: Create a New Python Script
Right click on your project folder
Select New  Python File
Name your script

9. Step 3: Write Some Pseudo Code

10. Step 4: Write Some Real Code

11. Some Hints Develop your solution as a script in PyCharm
The USGS website returns the data as a file, but you have to request it using a URL in your code. The Python module called “urllib2” (for Python 2.7) or “urllib3” for Python 3 is one option for downloading a file using a URL.
The data are returned in a text file where each new line represents a new date/time and data value. Each new line is delineated with a new line character. Each element within a line is delimited by a tab character.
Check out the Python “split” method for splitting a string based on a delimiter