Pandas：对随机数行求和

Question

我有以下代码生成随机整数的 100x100 数据帧：

import pandas as pd
import numpy as np

bin = []
cols = []
for i in range(1,101):
    cols.append("count_" + str(i))
    bin.append(i)

df = pd.DataFrame(np.random.randint(1,10,(100, 100)), index=bin, columns=cols)

    count_1  count_2  count_3  ... count_100
1   1        3        6        ... 9
2   2        8        4        ... 7
... ...      ...      ...      ... ...
100 6        3        8        ... 2

如果我想要列的总和，我可以使用：

df.sum()

给我

count_1      516
count_2      505
count_3      503
            ... 
count_98     534
count_99     489
count_100    521

但我想要行的总和。我该如何实现？

Answer 1

你可以df.sum(axis=1)

DataFrame.sum(axis=None, skipna=None, level=None, numeric_only=None, min_count=0, **kwargs)

Return the sum of the values over the requested axis.

This is equivalent to the method numpy.sum.

Parameters axis{index (0), columns (1)}: Axis for the function to be applied on.

Answer 2

bin = []
cols = []
for i in range(1,21):
   cols.append("count_" + str(i))
   bin.append(i)

df = pd.DataFrame(np.random.randint(1,10,(20, 20)), index=bin, columns=cols)
for col in cols:
    df[col]=df[col].astype(int) 

print(df.head())

fig,ax =plt.subplots(figsize=(16,8))
for item in df[cols].sum():
    print(item)
grouped=df[cols].sum().plot(kind='barh')


###########how to sum each row###########

df['sum']=0
for key,item in df.iterrows():
    sum=0
    for col in cols:
        sum+=df.loc[key,col]
    df.loc[key,'sum']=sum

 print (df.head())

Pandas：对随机数行求和

Pandas: sum rows of random numbers

python

pandas

python-3.8