本文介绍了如何在 Pandas 数据框中展开列的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着跟版网的小编来一起学习吧！
问题描述
I have the following pandas data frame:
import pandas as pd
import numpy as np
df = pd.DataFrame({
'fc': [100,100,112,1.3,14,125],
'sample_id': ['S1','S1','S1','S2','S2','S2'],
'gene_symbol': ['a', 'b', 'c', 'a', 'b', 'c'],
})
df = df[['gene_symbol', 'sample_id', 'fc']]
df
Which produces this:
Out[11]:
gene_symbol sample_id fc
0 a S1 100.0
1 b S1 100.0
2 c S1 112.0
3 a S2 1.3
4 b S2 14.0
5 c S2 125.0
How can I spread sample_id so that in the end I get this:
gene_symbol S1 S2
a 100 1.3
b 100 14.0
c 112 125.0
解决方案
Use pivot or unstack:
#df = df[['gene_symbol', 'sample_id', 'fc']]
df = df.pivot(index='gene_symbol',columns='sample_id',values='fc')
print (df)
sample_id S1 S2
gene_symbol
a 100.0 1.3
b 100.0 14.0
c 112.0 125.0
df = df.set_index(['gene_symbol','sample_id'])['fc'].unstack(fill_value=0)
print (df)
sample_id S1 S2
gene_symbol
a 100.0 1.3
b 100.0 14.0
c 112.0 125.0
But if duplicates, need pivot_table or aggregate with groupby or , mean can be changed to sum, median, ...:
df = pd.DataFrame({
'fc': [100,100,112,1.3,14,125, 100],
'sample_id': ['S1','S1','S1','S2','S2','S2', 'S2'],
'gene_symbol': ['a', 'b', 'c', 'a', 'b', 'c', 'c'],
})
print (df)
fc gene_symbol sample_id
0 100.0 a S1
1 100.0 b S1
2 112.0 c S1
3 1.3 a S2
4 14.0 b S2
5 125.0 c S2 <- same c, S2, different fc
6 100.0 c S2 <- same c, S2, different fc
df = df.pivot(index='gene_symbol',columns='sample_id',values='fc')
ValueError: Index contains duplicate entries, cannot reshape
df = df.pivot_table(index='gene_symbol',columns='sample_id',values='fc', aggfunc='mean')
print (df)
sample_id S1 S2
gene_symbol
a 100.0 1.3
b 100.0 14.0
c 112.0 112.5
df = df.groupby(['gene_symbol','sample_id'])['fc'].mean().unstack(fill_value=0)
print (df)
sample_id S1 S2
gene_symbol
a 100.0 1.3
b 100.0 14.0
c 112.0 112.5
EDIT:
For cleaning set columns name to None and reset_index:
df.columns.name = None
df = df.reset_index()
print (df)
gene_symbol S1 S2
0 a 100.0 1.3
1 b 100.0 14.0
2 c 112.0 112.5
这篇关于如何在 Pandas 数据框中展开列的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！
本站部分内容来源互联网,如果有图片或者内容侵犯了您的权益，请联系我们，我们会在确认后第一时间进行删除！