Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

Data Analysis Preparing Data for Analysis Data Cleaning Cleaning A CSV Part 2

Filling out missing values

At about minute 3 missing values of "Golbat" (row 42 of dataframe "data") are filled out. My question is how it is possible that a new object/row is created (golbat = data.loc[42]), values in it changed and then the values of the data frame (data) change correspondig? Aren't these to seperate objects? Which Python rule applies here? Thank you for your help!

golbat = data.loc[42]
golbat["Height (in)"] = 63
golbat["Weight (lbs)"] = 121.30


1 Answer

Mel Rumsey
.a{fill-rule:evenodd;}techdegree seal-36
Mel Rumsey
Treehouse Staff

Hey there kawa ! By creating golbat = data.loc[42] we are creating a reference to that specific row. When we change the values of weight and height for the referenced value, the values change in the dataframe.

Hello Mel, thank you for you answer! Is this a specialty of the pandas.loc() function? If the same principle applies, a should have the value of 2 aswell in the below example. Which it doesn't.

1. a = 1
2. b = 0
3. b = a 
4. b  = b + 1
# b=2 and a remains 1