df2.dropna(axis=0, how='any', subset=[u'ToC'], inplace=True)

print df.duplicated(['name']).value_counts()  # 如果不指定列，默认会判断所有列
"""
输出:
False    11118
True       664
表示有664行是重复的
"""

df.drop_duplicates(['name'], keep='last', inplace=True)
"""
keep : {‘first’, ‘last’, False}, default ‘first’
    first : Drop duplicates except for the first occurrence.
    last : Drop duplicates except for the last occurrence.
    False : Drop all duplicates.
"""