[Tutor] Error when trying to resample daily data to get a monthly average?

[Tyler Herrington]

Hello,

I am attempting to read in daily soil temperature data (and later on,
hourly data) from a csv file, and calculate monthly averaged soil
temperature from the data.

The data has a structure similar to: soil temperature data output
<https://i.stack.imgur.com/GumOt.png>

Basically, the goal is to loop through all the .csv files in the directory,
read in the daily (or hourly) soil temperature data from each csv file, and
then calculate a monthly mean from the data. However, it appears that the
timestamp may not be in the correct format for resample() to correctly read
and calculate the mean, as I get the following error: *TypeError: Only
valid with DatetimeIndex, TimedeltaIndex or PeriodIndex, but got an
instance of 'RangeIndex'*

def load_pandas(file_name):

    print("Loading file:", file_name)

    dframe = pd.read_csv(file_name)
    dframe.replace(-999, np.nan, inplace =True)
    levels = dframe.columns.values.tolist()

    print("Levels:", levels)
    print(levels[0])
    print("Column types:", dframe.dtypes)

    print(dframe)

    col1 = dframe[levels[0]]
    # Sample date: 2011-06-21 08:00:00
    date_fmt = "%Y-%m-%d %H:%M:%S"

    datetime_column = str_to_datetime(col1, date_fmt)
    # The pandas builtin seems to have issues
    #datetime_column = pd.to_datetime(dframe[levels[0]], date_fmt)
    print("Length of datetime column:", len(datetime_column))

    dframe_mon = dframe.resample('M').mean()
    print(dframe_mon)
def main():

    from pathlib import Path
    directory = "/praid/users/herringtont/soil_temp/In-Situ/GTN-P/"
    directory_as_str = str(directory)
    pathlist = Path(directory_as_str).glob('*.csv')
    for path in pathlist:
    # because path is object not string
        path_in_str = str(path)
        print(path_in_str)
        boreholes = path_in_str
        load_pandas(boreholes)



main()

Any suggestions on how to fix this issue?
Tyler Herrington, MSc
PhD Student (Climate Science)
Geography and Environmental Management
University of Waterloo