按dataframe中的每一行计算列中的唯一值
按dataframe中的每一行计算列中的唯一值
提问于 2022-10-29 21:32:09
我有一个dataframe (df)，它有两个列(学生编号，值)，一个列(值)，每行有多个逗号分隔的值。我想计算每行在该列中出现的唯一值的次数。
df看起来如下所示：
我想知道每个学生编号的“值”列中每个值(0和1)出现了多少次。
本例中的结果如下所示：
student vector
0 (15,12)
1 (10,11)
2 (8,10)
3 (13,6)
4 (9,16)( 15 , 12 )表示第一行中的数字(0)出现15次，数字(1)出现12次(学生编号0)。
( 10 , 11 )表示该数字(0)出现10次，数字(1)在第二行出现11次(学生编号1)等。
注意：
df.info()
# Column Non-Null Count Dtype
--- ------ -------------- -----
0 student 5 non-null int64
1 values 5 non-null object
dtypes: int64(1), object(1)
memory usage: 208.0+ bytes回答 1
Stack Overflow用户
回答已采纳
发布于 2022-10-29 21:38:53
因为在数据列中，不是字符串，而是数组，所以如果不匹配，可以将Counter与dict.get一起用于获取0：
from collections import Counter
def f(x):
d = Counter(x)
return ((d.get(0, 0), d.get(1, 0)))
df['vector'] = df['values'].apply(f)
print (df)
student values vector
0 0 [0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0] (9, 0)
1 1 [1.0,0.0,1.0,1.0,1.0,0.0,1.0,0.0,1.0] (3, 6)
2 2 [0.0,0.0,0.0,1.0,1.0,0.0,0.0,0.0,0.0] (7, 2)
3 3 [1.0,0.0,1.0,1.0,1.0,0.0,1.0,0.0,1.0] (3, 6)
4 4 [0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0] (9, 0)页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/74248991
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