如何計算 python 中每個日期時間和類別的頻率

Question

我有以下問題。

df_dict = {"uziv_id" : [1, 1, 2, 3], "datetime" : ["2022-09-05 07:25:12", "2022-09-05 07:25:52", "2022-09-05 07:42:12", "2022-09-05 07:43:12"],
           "expedice" : ["A", "A", "B", "A"]}

df = pd.DataFrame(df_dict)

我需要每 10 分鍾間隔和每個 expedice 計算expedice 。 我試試這個：

df["time"] = pd.to_datetime(df["datetime"])

df = (
    df.groupby(pd.Grouper(freq="10Min", key="time"), "exp")["uziv_id"]
    .nunique()
    .reset_index(name="count")
)
df = df.rename(columns={"time": "interval start"})
df.insert(1, "interval end", df["interval start"] + pd.Timedelta("10Min"))

但我得到一個錯誤ValueError: No axis named exp for object type DataFrame 。 請問我做錯了什么？

Answer 1

在groupby中使用 list [] ：

df["time"] = pd.to_datetime(df["datetime"])

df = (
    df.groupby([pd.Grouper(freq="10Min", key="time"), "expedice"])["uziv_id"]
    .nunique()
    .reset_index(name="count")
)
df = df.rename(columns={"time": "interval start"})
df.insert(1, "interval end", df["interval start"] + pd.Timedelta("10Min"))
print (df)
       interval start        interval end expedice  count
0 2022-09-05 07:20:00 2022-09-05 07:30:00        A      1
1 2022-09-05 07:40:00 2022-09-05 07:50:00        A      1
2 2022-09-05 07:40:00 2022-09-05 07:50:00        B      1