将 Pandas DataFrame 写入换行符分隔的 JSON
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Write Pandas DataFrame to newline-delimited JSON
提问by uspowpow
I started by reading a CSV into a Pandas Data Frame via the pandas read_csv() function. Now that the data is in an actual data frame, I tried to write something like this:
我首先通过 pandas read_csv() 函数将 CSV 读入 Pandas 数据帧。现在数据在一个实际的数据框中，我试着写这样的东西：
for row in df.iterrows():
row[1].to_json(path_to_file)
This works but only the last row is saved to disk because I've been rewriting the file each time I make a call to row[1].to_json(path_to_file). I've tried a few other file handling options but to no avail. Can anyone shed some insight on how to proceed?
这有效，但只有最后一行被保存到磁盘，因为我每次调用 row[1].to_json(path_to_file) 时都在重写文件。我尝试了其他一些文件处理选项，但无济于事。任何人都可以对如何进行一些了解吗？
Thank you!
谢谢！
回答by conradlee
To create newline-delimited json from a dataframe df, run the following
要从数据帧创建换行符分隔的 json df，请运行以下命令
df.to_json("path/to/filename.json",
orient="records",
lines=True)
Pay close attention to those optional keyword args! The linesoption was added in pandas 0.19.0.
密切注意那些可选的关键字参数！该lines选项已添加到 pandas 中0.19.0。
回答by Noah
You can pass a buffer in to df.to_json():
您可以将缓冲区传递给df.to_json()：
In [1]: import pandas as pd
In [2]: df = pd.DataFrame({"a":[1,3,5], "b":[1.1,1.2,1.2]})
In [3]: df
Out[3]:
a b
0 1 1.1
1 3 1.2
2 5 1.2
In [4]: f = open("temp.txt", "w")
In [5]: for row in df.iterrows():
row[1].to_json(f)
f.write("\n")
...:
In [6]: f.close()
In [7]: open("temp.txt").read()
Out[7]: '{"a":1.0,"b":1.1}\n{"a":3.0,"b":1.2}\n{"a":5.0,"b":1.2}\n'
回答by Jon Clements
If you're trying to write a DF using iterrows- I suspect you should be looking at:
如果您尝试使用以下方法编写 DF iterrows- 我怀疑您应该查看：
df.to_json(orient='records') # List of lists of values
# [[1, 2], [3,4]]
Or:
或者：
df.to_json(orient='records') # List of dicts with col->val
# [{'A': 1, 'B': 2}, {'A': 3, 'B': 4}]
Or writing a dict of {index:col value}:
或者写一个 {index:col value} 的字典：
df.A.to_json()
# {0: 1, 1: 3}
