python - 循环中从数据帧获取最大值和最小值

Question

这是我的数据框中的列列表:

a=list(aps1)
a
Out[107]: 
['ID',
 'class',
 'S3',
 'S22',
 'S23',
 'S26_3',
 'S28']

现在我正在尝试运行一个循环，该循环将获取每列的最大值和最小值并显示如下输出:

S3, Range in 0 to 100
S22, Range in 50 to 75

等等。对于循环，我使用了:

for columns in a:
    print(columns + ', Range in ' + round(aps1.columns.min()) + ' to ' + round(aps1.columns.max()))

但我收到以下错误:

TypeError: can only concatenate list (not "str") to list

仅针对一个变量运行时:

print ('S23, Range in ' + round(aps1.S23.min()) + ' to ' + round(aps1.S23.max()))

我得到:

TypeError: ufunc 'add' did not contain a loop with signature matching types dtype('<U21') dtype('<U21') dtype('<U21')

有人可以帮我吗？非常感谢。

Answer 1

使用格式:

for c in aps1.columns:
    print ('{}, Range in {} to {}'.format(c, aps1[c].min(), round(aps1[c].max())))

<小时/>

但更好的是使用 aggregate对于具有 min 和 max 的 DataFrame:

aps1 = pd.DataFrame({'S3':[4,5,4,5,5,4],
                   'S22':[7,8,9,4,2,3],
                   'S23':[1,3,5,7,1,0],
                   'S26':[5,3,6,9,2,4]})

print (aps1)
   S22  S23  S26  S3
0    7    1    5   4
1    8    3    3   5
2    9    5    6   4
3    4    7    9   5
4    2    1    2   5
5    3    0    4   4

df1 = aps1.agg(['min','max']).round()
print (df1)
     S22  S23  S26  S3
min    2    0    2   4
max    9    7    9   5

for c in df1.columns:
    print ('{}, Range in {} to {}'.format(c, s.loc['min', c], s.loc['max', c]))

S22, Range in 2 to 9
S23, Range in 0 to 7
S26, Range in 2 to 9
S3, Range in 4 to 5

<小时/>

for c in aps1.columns:
    print ('{}, Range in {} to {}'.format(c, aps1[c].min(), round(aps1[c].max())))

S22, Range in 2 to 9
S23, Range in 0 to 7
S26, Range in 2 to 9
S3, Range in 4 to 5