将列表中具有零值的多列添加到 Pandas 数据框中
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Add multiple columns with zero values from a list to a Pandas data frame
提问by arkisle
Say I have a data frame
说我有一个数据框
id col1 col2
1 1 foo
2 1 bar
And a list of column names
以及列名列表
l = ['col3', 'col4', 'col5']
How do I add new columns to the data frame with zero as values?
如何以零作为值向数据框中添加新列？
id col1 col2 col3 col4 col5
1 1 foo 0 0 0
2 1 bar 0 0 0
回答by Thtu
You could try direct assignment (assuming your dataframe is named df):
您可以尝试直接分配（假设您的数据框名为 df）：
for col in l:
df[col] = 0
Or use the DataFrame's assign method, which is a slightly cleaner way of doing it if lcan contain a value, an array or any pandas Series constructor.
或者使用 DataFrame 的 assign 方法，如果l可以包含值、数组或任何 Pandas Series 构造函数，则这是一种更简洁的方法。
# create a dictionary of column names and the value you want
d = dict.fromkeys(l, 0)
df.assign(**d)
Pandas Documentation on the assignmethod : http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.assign.html
关于该assign方法的Pandas 文档：http: //pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.assign.html
