Question

I am having a problem with my nested loops. I am getting an output, but it is duplicating each output for the number of fields in my data set.

for dat in data_body:
    x = float(dat[5])
    y = float(dat[6])
    point = ogr.Geometry(ogr.wkbPoint)
    point.AddPoint(x,y)
    feature.SetGeometry(point)
    for i, d in enumerate(dat):
        for j, field in enumerate(new_fields):
            if i == j:
                feature.SetField(field, d)
                layer.CreateFeature(feature)

For my datasets, the list of lists data_body has 13 rows of data and 55 columns (i.e. 55 positions). For my list new_fields I have a 55 values, which correspond to the columns of data_body list of lists. Thus, in my code block for the object feature.SetField(field, d). I should have each value of the data_body correspond to each unique field, as long as rows match each other, i.e. i and j. However, rather getting an object back with 13 rows of data corresponding with column values corresponding to the values in new_fields. I get 13 * 55 values, i.e. 715 rows, where values are missing for ~ 50% of the data. My output data table kind of looks like a triangle of data.

I am not sure if my question makes sense, but if it does, any help with my nested looping strategies would be helpful. i think my issue is my conceptualization of what my loop is actually doing, as well as what my if statement might be doing.

Answer 1

As avasal said, you want to iterate over dat and new_fields at the same time, and the easiest way to do this is to use zip:

for d, field in zip(dat, new_fields):
    feature.SetField(field, d)
    layer.CreateFeature(feature)