Using dictionary and dataframe to create new arrays with variable names with loop

Question

I am currently working to process some data that are imported to Python as a dataframe that has 10000 rows and 20 columns. The columns store sample names and chemical element. The daaaframe is currently indexed by both sample name and time, appearing as so: [1]: https://i.sstatic.net/7knqD.png .

From this dataframe, I want to create individual arrays for each individual sample, of which there are around 25, with a loop. I have generated an index and array of the sample names, which yields an array that appears as so

samplename = fuegodataframe.index.levels[0] samplearray = samplename.to_numpy()

array(['AC4-EUH41', 'AC4-EUH79N', 'AC4-EUH79S', 'AC4-EUH80', 'AC4-EUH81', 'AC4-EUH81b', 'AC4-EUH82N', 'AC4-EUH82W', 'AC4-EUH84', 'AC4-EUH85N', 'AC4_EUH48', 'AC4_EUH48b', 'AC4_EUH54N', 'AC4_EUH54S', 'AC4_EUH60', 'AC4_EUH72', 'AC4_EUH73', 'AC4_EUH73W', 'AC4_EUH78', 'AC4_EUH79E', 'AC4_EUH79W', 'AC4_EUH88', 'AC4_EUH89', 'bhvo-1', 'bhvo-2', 'bir-1', 'bir-2', 'gor132-1', 'gor132-2', 'gor132-3', 'sc ol-1', 'sc ol-2'], dtype=object)

I have also created a dictionary with keys of each of these variable names. I am now wondering how I would use this dictionary to generate individual variables for each of these samples that capture all the rows in which a sample is found.

I have tried something along these lines:

for ii in sampledictionary.keys():
     if ii == sampledictionary[ii]: 
        sampledictionary[ii] = fuegodataframe.loc[sampledictionary[ii]]

but this fails. How would I actually go about doing something like this? Is this possible?

SarahJessica · Accepted Answer · 2019-11-17 18:03:05Z

1

I think you're asking how to generate variables dynamically rather than assign your output to a key in your dictionary.

In Python there is a globals function globals() that will output all the variable names defined in the document.

You can assign new variables dynamically to this dictionary

globals()[f'variablename_{ii}'] = fuegodataframe.loc[sampledictionary[ii]]

etc.

if ii was 0 then variablename_0 would be available with the assigned value.

In general this is not considered good practice but it is required sometimes.

answered Nov 17, 2019 at 18:03

SarahJessica

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2 Comments

ShpielMeister Over a year ago

clever and sometimes useful

ShpielMeister Over a year ago

globals() is a dictionary so it can be added to: >>> cheat Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'cheat' is not defined >>> type(globals())<class 'dict'> >>> globals()['cheat'] = 123 >>> cheat 123 p.s likewise for locals()

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