查找列表中大于当前元素的所有元素

Question

If I have an array in Python in which all of the elements have different values, eg [1,4,6,2,10,3,5] , is there a way to find the total number of values in the list that are greater than the current index?

So for example, using the above list of length 7, the result I'd like to get is another list of length 7 which looks like [6,3,1,5,0,4,2] . I was having trouble trying to loop through the list (the code I tried to use is below)

for i in data:
    count = np.sum(data > data[i])
    N[i]=count

where data is the array containing all the pertaining values and N is an np.zeros list of the same length as data

Answer 1

Here is my suggestion:

We sort the original list (l) and save it in a new list m. We create a new list (k) where we save the count of elements that are found on the right of the position of each element in m. See below:

l=[1,4,6,2,10,3,5]

m=sorted(l)
#[1, 2, 3, 4, 5, 6, 10]

k=[]
for i in l:
    k.append(len(m)-m.index(i)-1)

>>> print(k)

[6, 3, 1, 5, 0, 4, 2]

Answer 2

You were very close. for i in data iterates through each element , not the indices as in Java/C.

Use range(len(data)) instead.

import numpy as np

data = np.array([1,4,6,2,10,3,5])
out = np.array([0]*7)

for i in range(len(data)):
    count = np.sum(data > data[i])
    out[i] = count

print(out)  # [6 3 1 5 0 4 2]

Another way to write the loop is to use enumerate() , which returns an iterator of pairs of (indices, elements).

for i, x in enumerate(data):
    count = np.sum(data > x)
    out[i] = count

Answer 3

Something like this?

list = [1,4,6,2,10,3,5]
list2 = []
v = len(list)
for x in list:
    if x > v:
        pass
    else:
        list2.append(x)

print(list2)

EDIT ¯\_(ツ)_/¯ (To see the total number of elements greater than the current element)

list = [1,4,6,2,10,3,5]
list2 = []
v = len(list)
total = 0

for x in list:
    if x > v:
        pass
    else:
        list2.append(x)

for y in list2:
    total += 1

list2 = str(list2).replace('[', '')
list2 = list2.replace(']', '')

print("Now - " + list2 + ", in total of " + str(total) + " numbers ;)")

Output -

Now - 1, 4, 6, 2, 3, 5, in total of 6 numbers ;)

Answer 4

Alternatively, you can do it by using vectorize as follows:

>>> data = np.array( [1,4,6,2,10,3,5] )
>>> np.vectorize(lambda a, b : np.sum(a>b), excluded = [0] )(data, data)
array([6, 3, 1, 5, 0, 4, 2])