从 csv 文件读取时，pandas 添加列
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pandas add columns when read from a csv file
提问by running man
I want to read from a CSV file using pandas read_csv. The CSV file doesn't have column names. When I use pandas to read the CSV file, the first row is set as columns by default. But when I use df.columns = ['ID', 'CODE'], the first row is gone. I want to add, not replace.
我想使用 pandas 从 CSV 文件中读取read_csv。CSV 文件没有列名。当我使用 Pandas 读取 CSV 文件时，第一行默认设置为列。但是当我使用时df.columns = ['ID', 'CODE']，第一行不见了。我想添加，而不是替换。
df = pd.read_csv(CSV)
df
a 55000G707270
0 b 5l0000D35270
1 c 5l0000D63630
2 d 5l0000G45630
3 e 5l000G191200
4 f 55000G703240
df.columns=['ID','CODE']
df
ID CODE
0 b 5l0000D35270
1 c 5l0000D63630
2 d 5l0000G45630
3 e 5l000G191200
4 f 55000G703240
回答by jezrael
I think you need parameter namesin read_csv:
我认为你需要参数names在read_csv：
df = pd.read_csv(CSV, names=['ID','CODE'])
names: array-like, default None
List of column names to use. If file contains no header row, then you should explicitly pass header=None. Duplicates in this list are not allowed unless mangle_dupe_cols=True, which is the default.
名称：类似数组，默认无
要使用的列名称列表。如果文件不包含标题行，那么您应该明确传递 header=None。除非 mangle_dupe_cols=True，这是默认值，否则不允许在此列表中重复。
回答by ZdaR
You may pass the column names at the time of reading the csv file itself as :
您可以在读取 csv 文件本身时将列名传递为：
df = pd.read_csv(csv_path, names = ["ID", "CODE"])
回答by Carles Mitjans
Use namesargument in function call to add the columns yourself:
names在函数调用中使用参数自己添加列：
df = pd.read_csv(CSV, names=['ID','CODE'])
回答by MaxU
you need both: header=Noneand names=['ID','CODE'], because there are no column names/labels/headers in your CSV file:
您同时需要:header=None和names=['ID','CODE']，因为您的 CSV 文件中没有列名/标签/标题：
df = pd.read_csv(CSV, header=None, names=['ID','CODE'])
