2), columns=list("AB")) In [538]: st = pd.HDFStore("appends.h5", mode="w") In [539]: st.append("df", df_1, data_columns=["B"], index=False) In [540]: st.append("df", df_2, data_columns=["B"], index=False) In [54
import polars as pl import time # 读取 CSV 文件 start = time.time() df_pl = pl.read_csv('test_data.csv') load_time_pl = time.time() - start # 过滤操作 start = time.time() filtered_pl = df_pl.filter(pl.col('value1') > 50) filter_time_pl = time.time() - start # 分组...
df.filter(regex='Q', axis=1) # 列名包含Q的列 df.filter(regex='e$', axis=1) # 以e结尾的列 df.filter(regex='1$', axis=0) # 正则,索引名以1结尾 df.filter(like='2', axis=0) # 索引中有2的 # 索引中以2开头、列名有Q的 df.filter(regex='^2',axis=0).filter(like='Q', ...
AI代码解释 math_score=df.set_index(['Gender','School'])['Math'].sort_index()grouped_score=df.set_index(['Gender','School']).sort_index().\groupby(lambda x:(x,'均分及格'ifmath_score[x].mean()>=60else'均分不及格'))forname,_ingrouped_score:print(name) d). groupby的[]操作 可...
pandas数据选取4(query/eval/filter/where/mask) #query函数a = {"name":["lemon","jack","peter","Emma","james"],"city":["长沙","上海","深圳","北京","北京"],"a":[80,90,60,73,89],"b":[80,75,80,85,83],"c":[70,75,80,73,62]}...
lsin () 用于过滤数据帧。Isin () 有助于选择特定列中具有特定(或多个)值的行。 # Using the dataframe we created for read_csvfilter1 = df["value"].isin([112])filter2 = df["time"].isin([1949.000000])df [filter1 & filter2]
6. where()Where() 用于从满足特定条件的数组中返回元素。它返回在特定条件下值的索引位置。这差不多类似于在SQL中使用的where语句。请看以下示例中的演示。y = np.array([1,5,6,8,1,7,3,6,9])# Where y is greaterthan 5, returns index position np.where(y>5)array([2, 3, 5, 7, 8], ...
df.filter(items=['Q1', 'Q2']) # 选择两列df.filter(regex='Q', axis=1) # 列名包含Q的列df.filter(regex='e$', axis=1) # 以e结尾的列df.filter(regex='1$', axis=0) # 正则,索引名以1结尾df.filter(like='2', axis=0) # 索引中有2的# 索引...
df.filter(regex='e$', axis=1) # 以e结尾的列 df.filter(regex='1$', axis=0) # 正则,索引名以1结尾 df.filter(like='2', axis=0) # 索引中有2的 # 索引中以2开头、列名有Q的 df.filter(regex='^2',axis=0).filter(like='Q', axis=1) ...
DataFrame.filter(item=None,# 索引名称中是否包含设置内容like=None,# 模糊指定索引名称中是否包含设置内容regex=None,# 通过正则表达式来指定索引名称中是否包含设置的内容axis=None# 轴方向的设置) 1. 2. 3. 4. 5. 6. 15. where 符合要求的返回对应值,不符合的数据修改为指定值,默认为NA ...