当列不相同时，如何向dataframe中添加行？

Question

例如，我有四列的原始数据框，称为“old_data”：

name type age location

然后我需要在这个数据框中添加一些新行，但它只有两列：

name age

要添加的新数据是一个DICT列表，称为“新数据”：

[{name:age}, {name:age}, {name:age}]

列不匹配时如何执行此操作

Answer 1

import pandas as pd

# original data-frame
df = pd.DataFrame([{"name":"john", "type":"", "age":"12", "location":"so"},
                   {"name":"jane", "type":"", "age":"12", "location":"so"}])

# convert existing dict to array of dict's
data = {"james":"20", "rich":"30"}
new_df = pd.DataFrame([{"name":k, "age":v} for k, v in data.items()])

# use data-frame append to add to existing df, missing values will be filled with NaN
df = df.append(new_df, ignore_index=True)

print(df)

输出

  age location   name type
0  12       so   john     
1  12       so   jane     
2  20      NaN  james  NaN
3  30      NaN   rich  NaN