[英]Python pandas - writing groupby output to file
I used the following to get proportion information on my data:我使用以下方法获取有关我的数据的比例信息:
>>>testfile = pd.read_csv('CCCC_output_all_FINAL.txt', delimiter="\t", header=0)
>>> testdf = pd.DataFrame({'Proportion': testfile.groupby(('Name','Chr','Position','State')).size() / 39})
>>> testdf.head(5)
Proportion
Name Chr Position State
S-3AAAA 16 27557749 4 0.025641
5 0.076923
6 0.025641
S-3AAAC 15 35061490 2 0.076923
4 0.025641
>>> testdf.to_csv('CCCC_output_summary.txt', sep='\t', header=True, index=False)
The output file only has the column Proportion
. output 文件只有
Proportion
列。 I'd like the following table output:我想要下表 output:
Name Chr Position State Proportion
S-3AAAA 16 27557749 4 0.025641
S-3AAAA 16 27557749 5 0.076923
S-3AAAA 16 27557749 6 0.025641
S-3AAAC 15 35061490 2 0.076923
S-3AAAC 15 35061490 4 0.025641
Is it possible/easy to write the pandas output to a file like this?是否可以/容易地将 pandas output 写入这样的文件?
使用reset_index()
:
testdf.reset_index().to_csv('CCCC_output_summary.txt', sep='\t', header=True, index=False)
Recently, I had to work with an Excel file that has 2 columns, with headers 'Dog Breed' and 'Dog Name'.最近,我不得不处理一个 Excel 文件,该文件有 2 列,标题为“Dog Breed”和“Dog Name”。 I came up with the following code (tested with
Python 3.11.0
) that uses groupby()
and prints the grouped data into a .csv
file.我想出了以下代码(使用
Python 3.11.0
测试),它使用groupby()
并将分组数据打印到.csv
文件中。
from pathlib import Path
import pandas as pd
p = Path(__file__).with_name('data.xlsx')
q = Path(__file__).with_name('data-grouped.csv')
df = pd.read_excel(p)
groups = df.groupby('Dog Breed', sort=False)
with q.open('w') as foutput:
for g in groups: # For each group
foutput.write(f"{g[0]}, {len(g[1])}") # Record the number of dogs in each group
for e, (index, row) in enumerate(g[1].iterrows()): # Iterating over the group's dataframe
name = str(row['Dog Name'])
if(e == 0):
mystr = f",{name}\n"
else:
mystr = f",,{name}\n"
foutput.write(mystr)
data.xlsx:
data-grouped.csv:
I had the same problem. 我有同样的问题。 reset_index() as explained above did not work for me.
如上所述的reset_index()对我不起作用。 I used an answer from another Stackoverflow and it worked wonderfully.
我使用了另一个Stackoverflow的答案,效果很好。 Details are below.
详细信息如下。
Input csv has data under following two columns: Item Code, Quantity 输入的csv在以下两列中包含数据:项目代码,数量
Output needed: Average quantity grouped by item and both columns to be part of csv. 需要的输出:按项目和两列分组的平均数量,将其作为csv的一部分。
Initial code: 初始代码:
import pandas as pd
data_directory = os.path.join("D:\\data")
df = pd.read_csv(os.path.join(data_directory, "input_file.csv"))
df_avg = df.groupby("Item Code")["Quantity"].mean()
df_avg.reset_index().to_csv(os.path.join(data_directory,'output_file.csv'), sep='\t', header=True, index=False )
Output received: Only the average quantity was written to output file 收到输出:仅将平均数量写入输出文件
Following code solved the problem: 以下代码解决了该问题:
import pandas as pd
data_directory = os.path.join("D:\\data")
df = pd.read_csv(os.path.join(data_directory, "input_file.csv"))
df.groupby("Item Code")["Quantity"].mean().reset_index()[["Item Code", "Quantity"]].to_csv(os.path.join(data_directory,'output_file.csv'))
By the above code, I got the output file which has two columns: Item Code and Quantity and the second column contains average of quantity for each Item code. 通过上面的代码,我得到了包含两列的输出文件:项目代码和数量,第二列包含每个项目代码的数量平均值。
Other stack overflow reference: Pandas groupby to to_csv 其他堆栈溢出参考: Pandas groupby到to_csv
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