how to select index column pandas code example

Example 1: pandas df by row index

indices = [133, 22, 19, 203, 14, 1]
df_by_indices = df.iloc[indices, :]

Example 2: pandas row data to webform

def _getFields(obj, tree=None, retval=None, fileobj=None):
    fieldAttributes = {'/FT': 'Field Type', '/Parent': 'Parent', '/T': 'Field Name', 
    '/TU': 'Alternate Field Name', '/TM': 'Mapping Name', '/Ff': 'Field Flags', 
    '/V': 'Value', '/DV': 'Default Value'}
    if retval is None:
        retval = OrderedDict()
        catalog = obj.trailer["/Root"]
        if "/AcroForm" in catalog:
            tree = catalog["/AcroForm"]
        else:
            return None
    if tree is None:
        return retval

    obj._checkKids(tree, retval, fileobj)
    for attr in fieldAttributes:
        if attr in tree:
            obj._buildField(tree, retval, fileobj, fieldAttributes)
            break

    if "/Fields" in tree:
        fields = tree["/Fields"]
        for f in fields:
            field = f.getObject()
            obj._buildField(field, retval, fileobj, fieldAttributes)

    return retval

Example 3: add an index column in range dataframe

df = df.loc[df.index.repeat(df['a'])]   
df['c'] = df.groupby(level=0).cumcount() + 1
df = df.reset_index(drop=True)
print (df)
   a  b  c
0  1  x  1
1  2  y  1
2  2  y  2
3  3  z  1
4  3  z  2
5  3  z  3