1.根据某个列进行groupby，判断是否存在重复列。
# Count the unique variables (if we got different weight values, # for example, then we should get more than one unique value in this groupby) all_cols_unique_players = df.groupby('playerShort').agg({col:'nunique' for col in player_cols}) 其中针对.agg函数：
DataFrame.agg(selffuncaxis=0*args**kwargs)[source]
Aggregate using one or more operations over the specified axis.
例子：
>>> df = pd.DataFrame([[1, 2, 3], ... [4, 5, 6], ... [7, 8, 9], ... [np.nan, np.nan, np.nan]], ... columns=['A', 'B', 'C']) >>> df.agg({'A' : ['sum', 'min'], 'B' : ['min', 'max']}) A B max NaN 8.0 min 1.0 2.0 sum 12.0 NaN 2.获取一个字表
player_index = 'playerShort' player_cols = [#'player', # drop player name, we have unique identifier 'birthday', 'height', 'weight', 'position', 'photoID', 'rater1', 'rater2', ] def get_subgroup(dataframe, g_index, g_columns): """Helper function that creates a sub-table from the columns and runs a quick uniqueness test.""" g = dataframe.groupby(g_index).agg({col:'nunique' for col in g_columns}) if g[g > 1].dropna().shape[0] != 0: print("Warning: you probably assumed this had all unique values but it doesn't.") return dataframe.groupby(g_index).agg({col:'max' for col in g_columns}) players = get_subgroup(df, player_index, player_cols) players.head() 3.将整理出的字表存储至CSV文件
def save_subgroup(dataframe, g_index, subgroup_name, prefix='raw_'): save_subgroup_filename = "".join([prefix, subgroup_name, ".csv.gz"]) dataframe.to_csv(save_subgroup_filename, compression='gzip', encoding='UTF-8') test_df = pd.read_csv(save_subgroup_filename, compression='gzip', index_col=g_index, encoding='UTF-8') # Test that we recover what we send in if dataframe.equals(test_df): print("Test-passed: we recover the equivalent subgroup dataframe.") else: print("Warning -- equivalence test!!! Double-check.") 4.数据具体指标查看---缺失值查看
import missingno as msno import pandas_profiling
msno.matrix(players.sample(500), figsize=(16, 7), width_ratios=(15, 1))
msno.heatmap(players.sample(500), figsize=(16, 7),)
5.数据透视表
转至https://blog.csdn.net/Dorisi_H_n_q/article/details/82288092
透视表概念：pd.pivot_table()
透视表是各种电子表格程序和其他数据分析软件中一种常见的数据汇总工具。它根据一个或多个键对数据进行聚合，并根据行和列上的分组键将数据分配到各个矩形区域中。
透视表：根据特定条件进行分组计算，查找数据，进行计算 pd.pivot_table(df,index=['hand'],columns=['male'],aggfunc='min')
交叉表概念：pd.crosstab(index,colums)
交叉表是一种用于计算分组频率的特殊透视图,对数据进行汇总。
pd.crosstab(players.rater1, players.rater2)
fig, ax = plt.subplots(figsize=(12, 8)) sns.heatmap(pd.crosstab(players.rater1, players.rater2), cmap='Blues', annot=True, fmt='d', ax=ax) ax.set_title("Correlation between Rater 1 and Rater 2\n") fig.tight_layout() 
创建一个新列，新列的值是另外两列的平均值
players['skintone'] = players[['rater1', 'rater2']].mean(axis=1) players.head()
6.对离散category数值进行处理
position_types = players.position.unique() position_types “”“ array(['Center Back', 'Attacking Midfielder', 'Right Midfielder', 'Center Midfielder', 'Goalkeeper', 'Defensive Midfielder', 'Left Fullback', nan, 'Left Midfielder', 'Right Fullback', 'Center Forward', 'Left Winger', 'Right Winger'], dtype=object) ”“” defense = ['Center Back','Defensive Midfielder', 'Left Fullback', 'Right Fullback', ] midfield = ['Right Midfielder', 'Center Midfielder', 'Left Midfielder',] forward = ['Attacking Midfielder', 'Left Winger', 'Right Winger', 'Center Forward'] keeper = 'Goalkeeper' # modifying dataframe -- adding the aggregated position categorical position_agg players.loc[players['position'].isin(defense), 'position_agg'] = "Defense" players.loc[players['position'].isin(midfield), 'position_agg'] = "Midfield" players.loc[players['position'].isin(forward), 'position_agg'] = "Forward" players.loc[players['position'].eq(keeper), 'position_agg'] = "Keeper"
绘制value_counts()图片
MIDSIZE = (12, 8) fig, ax = plt.subplots(figsize=MIDSIZE) players['position_agg'].value_counts(dropna=False, ascending=True).plot(kind='barh', ax=ax) ax.set_ylabel("position_agg") ax.set_xlabel("Counts") fig.tight_layout() 
7.绘制多变量之间的关系图
from pandas.plotting import scatter_matrix fig, ax = plt.subplots(figsize=(10, 10)) scatter_matrix(players[['height', 'weight', 'skintone']], alpha=0.2, diagonal='hist', ax=ax);
# Perhaps you want to see a particular relationship more clearly
fig, ax = plt.subplots(figsize=MIDSIZE) sns.regplot('weight', 'height', data=players, ax=ax) ax.set_ylabel("Height [cm]") ax.set_xlabel("Weight [kg]") fig.tight_layout() 
8.连续变量离散化（Create quantile bins for continuous variables）
weight_categories = ["vlow_weight", "low_weight", "mid_weight", "high_weight", "vhigh_weight", ] players['weightclass'] = pd.qcut(players['weight'], len(weight_categories), weight_categories)
9.数据报表查看
pandas_profiling.ProfileReport(players)
10.出生日期等时间格式处理
players['birth_date'] = pd.to_datetime(players.birthday, format='%d.%m.%Y') players['age_years'] = ((pd.to_datetime("2013-01-01") - players['birth_date']).dt.days)/365.25 players['age_years'] //选择特定列 players_cleaned_variables = players.columns.tolist() players_cleaned_variables
player_dyad = (clean_players.merge(agg_dyads.reset_index().set_index('playerShort'), left_index=True, right_index=True)) //groupby+sort_values+rename (tidy_dyads.groupby(level=1) .sum() .sort_values('redcard', ascending=False) .rename(columns={'redcard':'total redcards received'})).head()