想知道如何通过考虑两列在 python 数据框中使用 startswith

Question

我的输入是（A,B有数据，需要在C列输出）

逻辑是。如果我在 A 和 B 列中的前四个字母是 INKA 或 IDKA，那么输出是 KAR。

同样的方式 INAP 或 IDAP 然后 AP 和 INRJ 或 IDRJ 然后 RAJ

输入为A和B，期望输出为C。

A	B	C
IDKA106829_KMGL_H_Z_8121	INKA100345_KMGL_H_Z_8251	KAR
IDKA101971_KUDU_H_Z_8251	YEDTHADY-IND	KAR
SIRA_RPTR	IDKA102853_KSIR_H_Z_8251	KAR
IDAP104327_PEDA_H_Z_8251	IDAP104769_URUM_H_Z_8251	AP
IDAP103547_RAMP_H_Z_8251	MADDIRALA	AP
SALURU	IDAP103620_SALU_H_Z_8251	AP
IDRJ103411_KOTA_H_Z_8251	KOT009	RAJ
IDRJ100041_BKNR_H_Z_8251	INRJ200420_BKNR_H_Z_8251	RAJ
JAIPR203	INRJ200420_BKNR_H_Z_8251	RAJ

Answer 1

你可以通过迭代来做到这一点，从开始，如果不是！像这样！

dataframe = [
['IDKA106829_KMGL_H_Z_8121','INKA100345_KMGL_H_Z_8251',''],
['IDRJ100041_BKNR_H_Z_8251','INRJ200420_BKNR_H_Z_8251','']
]

for row in dataframe:
    for column in row:
        if column.startswith('IDKA') or column.startswith('INKA'):
            row[2] = 'KAR'
        elif column.startswith('INJR') or column.startswith('IDRJ'):
            row[2] = 'RAJ'

print (dataframe)

Answer 2

您可以使用 np.select:

conditions = [(df["A"].str[:4].isin(["INKA", "IDKA"]))|(df["B"].str[:4].isin(["INKA", "IDKA"])),
              (df["A"].str[:4].isin(["INAP", "IDAP"]))|(df["B"].str[:4].isin(["INAP", "IDAP"])),
              (df["A"].str[:4].isin(["INRJ", "IDRJ"]))|(df["B"].str[:4].isin(["INRJ", "IDRJ"]))]

df["C"] = np.select(conditions, ["KAR", "AP", "RAJ"], None)

或者，您可以使用 map 和 combine_first:

mapper = {"INKA": "KAR", "IDKA": "KAR", "INAP": "AP", "IDAP": "AP", "INRJ": "RAJ", "IDRJ": "RAJ"
df["C"] = df["A"].str[:4].map(mapper).combine_first(df["B"].str[:4].map(mapper))

Answer 3

配合使用startswith and np.select.

conditions = [df['A'].str.startswith('INKA') | df['B'].str.startswith('INKA') | df['A'].str.startswith('IDKA') | df['B'].str.startswith('IDKA'),
              df['A'].str.startswith('INAP') | df['B'].str.startswith('INAP') | df['A'].str.startswith('IDAP') | df['B'].str.startswith('IDAP'),
              df['A'].str.startswith('INRJ') | df['B'].str.startswith('INRJ') | df['A'].str.startswith('IDRJ') | df['B'].str.startswith('IDRJ')]
 
choices = ['KAR','AP', 'RAJ']
 
df['C'] = np.select(conditions, choices, default=None)

结果 df:

想知道如何通过考虑两列在 python 数据框中使用 startswith

want to know how to use startswith in python dataframe by considering two columns

python

dataframe

numpy-slicing