How do I access a single Pandas DataFrame element?-CodePudding

I have a dataframe with three columns: date, file (filenames), and gcc (a float value). I'm trying to grab the filenames for the first, last, and middle dates. Since my dates are not in order, I found out that I can find the first and last using the min() and max(). I'm not sure how to grab the middle value, but that's not the problem. I can successfully index the first and last filenames, but I cannot figure out how to pass that indexed string to my image read function (matlibplot: imread()). Please see the code I'm using and the output below:

Generalized code:

print(df['file'][df.index[df['date'] == df['date'].min()].tolist()])

print(df.index[df['date'] == df['date'].min()].tolist())

print(df['file'][85])

Output:

85    B2AVNE_10_01_21_11_05.jpg
Name: file, dtype: object

[85]

B2AVNE_10_01_21_11_05.jpg

In the first line, I attempt to do what I want. Instead, I'm returned this Pandas object instead of the string I want.

In the second line, I ensure that the indexing code I'm using outputs the row number of the string that I want.

In the third line, I ensure that indexing the dataframe using that row number does indeed produce the string I want.

I cannot understand or find a solution to the disconnect between the first line of code and the next two lines of code.

CodePudding user response：

You can get it out like this by indexing for the specific row in the column:

df['file'].iloc[df['date'].argmin()]

EDIT:

Additional note:

df['date'].argmin() resolves to the index position of the minimum value, which is equivalent to your third attempt if your dataframe's index is ranging from 0 to n.

Also, iloc helps guarantee you are indexing based on position instead of the column's index ,which might not be in proper order or range from 0 to n (just a precautionary measure).