如何让这个 function 决定是否为真，而不是除以变量？

Question

Im writing a program to determine the positivity rate in icu's. I give a list: in_hospitals and in_icu, and I need to divide only the True values in the list by the true values to get the positivity rate %

This is the list:

in_hospitals = [True, True, False, True, False, True, True, True]
in_icu= [True, False, False, False, False, False, True, False]

The function:

def rate_icu(hospitals, icu):
                        hospitalized =  len(icu) / len(hospital) 
                        rate = hospitalized
                        return rate 


rate = rate_icu(hospitals, icu)
print(rate) #Testing Code

The function returns 1 because it just divides 8 by 8, but I need it to divide only the True values in the list above

Desired Output:

33.333333333333336

Answer 1

You can take advantage of the fact that True is 1 and False is 0 . With that, you can take the sum of the lists rather than the length:

in_hospitals = [True, True, False, True, False, True, True, True]
in_icu= [True, False, False, False, False, False, True, False]

def rate_icu(hospitals, icu):
                        hospitalized =  sum(icu) / sum(hospitals) 
                        rate = hospitalized
                        return rate 


rate = rate_icu(in_hospitals, in_icu)
print(rate) #Testing Code

# 0.3333333333333333

Of course if you want 33.33 you will need to multiply by 100.

Answer 2

The "obvious" way is to count the quantity of True in each list:

icu.count(True) / hospital.count(True)

The "short-cut" way is to know that Boolean is a derived from int , with True = 1 and False = 0: simply use sum :

sum(icu) / sum(hospital)

Answer 3

You should use sum instead of len :

    in_hospitals = [True, True, False, True, False, True, True, True]
    in_icu= [True, False, False, False, False, False, True, False]

    def rate_icu(hospitals, icu):
        hospitalized = (sum(icu) / sum(hospital)) * 100
        return hospitalized 


    rate = rate_icu(in_hospitals, in_icu)
    print(rate) #Testing Code

Answer 4

You need to filter the array

in_hospitals = [True, True, False, True, False, True, True, True]
in_icu = [True, False, False, False, False, False, True, False]


def rate_icu(hospital, icu):
    rate = len(icu) / len(hospital)
    return rate


rate = rate_icu([x for x in in_hospitals if x is True], [x for x in in_icu if x is True])
print(rate)

Answer 5

I would use sum

in_hospitals = [True, True, False, True, False, True, True, True]
in_icu= [True, False, False, False, False, False, True, False]

def rate_icu(hospitals, icu):
                        hospitalized =  sum(icu) / sum(hospitals) 
                        rate = hospitalized * 100
                        return rate 


rate = rate_icu(in_hospitals, in_icu)
print(f"{rate} %")