python的等价物是什么;R中的idxmin()是什么?

python的等价物是什么;R中的idxmin()是什么?,r,R,我经常遇到这样的情况:我必须在表中找到值的第一个实例。例如,下面我必须找到按顺序排序的每个candy_类型的第一个实例的颜色: d = {'candy_type':['A','A','B','B','C','C','C'],'sequence':[2,1,1,2,2,3,1], 'color':['Red','Black','Green','Yellow','Orange','White','Purple']} df = pd.DataFrame(data=d) df +----+-------

我经常遇到这样的情况:我必须在表中找到值的第一个实例。例如,下面我必须找到按顺序排序的每个candy_类型的第一个实例的颜色:

d = {'candy_type':['A','A','B','B','C','C','C'],'sequence':[2,1,1,2,2,3,1], 'color':['Red','Black','Green','Yellow','Orange','White','Purple']}
df = pd.DataFrame(data=d)
df
+----+--------------+------------+---------+
|    | candy_type   |   sequence | color   |
|----+--------------+------------+---------|
|  0 | A            |          2 | Red     |
|  1 | A            |          1 | Black   |
|  2 | B            |          1 | Green   |
|  3 | B            |          2 | Yellow  |
|  4 | C            |          2 | Orange  |
|  5 | C            |          3 | White   |
|  6 | C            |          1 | Purple  |
+----+--------------+------------+---------+
#sort the dataframe by each candy_type's sequence and reset the index
df_sorted = df.sort_values(['candy_type','sequence']).reset_index(drop=True)

#make the index into a column
df_sorted_index = df_sorted.reset_index(drop=False)

df_sorted_index
+----+---------+--------------+------------+---------+
|    |   index | candy_type   |   sequence | color   |
|----+---------+--------------+------------+---------|
|  0 |       0 | A            |          1 | Black   |
|  1 |       1 | A            |          2 | Red     |
|  2 |       2 | B            |          1 | Green   |
|  3 |       3 | B            |          2 | Yellow  |
|  4 |       4 | C            |          1 | Purple  |
|  5 |       5 | C            |          2 | Orange  |
|  6 |       6 | C            |          3 | White   |
+----+---------+--------------+------------+---------+

#find the first instance of each candy type; show the whole row 
df_sorted_index.loc[df_sorted_index.groupby('candy_type')['index'].idxmin()]
+----+---------+--------------+------------+---------+
|    |   index | candy_type   |   sequence | color   |
|----+---------+--------------+------------+---------|
|  0 |       0 | A            |          1 | Black   |
|  2 |       2 | B            |          1 | Green   |
|  4 |       4 | C            |          1 | Purple  |
+----+---------+--------------+------------+---------+

您可以使用
匹配

##创建排序数据.frame

d您可以使用
match

##创建排序数据.frame
d
哪个.min()
是R的等价物idxmin()。两者都在数组中查找最小值,并返回第一个这样的值的索引-如果存在关联,则非常有用。

哪个.min()是R的等价项idxmin()。两者都在数组中查找最小值并返回第一个这样的值的索引—如果存在关系,则非常有用