Python - 如何用字符串计算二维列表中的整数？

Question

I should create a program to calculate max, min and avg temperature in the list. List contain name of month, max and min temperature in this month:

  months =   [ ["January", 6,3],
               ["February", 7,3],
               ["March", 10,4],
               ["April", 13,6],
               ["May", 17,9],
               ["June", 20,12],
               ["July", 22,14],
               ["August", 21,14],
               ["September",19,12],
               ["October", 14,9],
               ["November", 10,6],
               ["December", 7,3] ]

I have played a bit with code to find out how can I calculate max temperature by using for loop, but it's not working as planned:

for m in months:
        for temp in m:
            if temp > temp1:
                temp = maxTemp
                print(temp)
                

I'm receiving TypeError:'>' not supported between instances of 'str' and 'int'

What is a correct way to work with list that contain strings in my case?

Answer 1

You're running the for loop through all elements in the list, to look only at the temperatures, you could use

for m in months:
    for temp in m[1:]:

which looks only at the integer elements in the list which are the 2nd and 3rd element, and ignores the 1st element which is a string and cannot be compared with integers (and that's the source of your error as well).

Answer 2

Your first for loop will yield not the month name, but the list containing ['Mont name', temp1, temp2] .

So, your code should be as follows:

for m in months:
    m_name = m[0]
    temp_vals = m[1:]  # if you have more than two temperature values
    
    temp_min = min(temp_vals)
    temp_avr = sum(temp_vals)/len(temp_vals)
    temp_max = max(temp_vals)

    print(f'{m_name}: T_min = {temp_min}; T_avr = {temp_avr}; T_max = {temp_max};')

Which gives:

January: T_min = 3; T_avr = 4.5; T_max = 6;
February: T_min = 3; T_avr = 5.0; T_max = 7;
March: T_min = 4; T_avr = 7.0; T_max = 10;
April: T_min = 6; T_avr = 9.5; T_max = 13;
May: T_min = 9; T_avr = 13.0; T_max = 17;
June: T_min = 12; T_avr = 16.0; T_max = 20;
July: T_min = 14; T_avr = 18.0; T_max = 22;
August: T_min = 14; T_avr = 17.5; T_max = 21;
September: T_min = 12; T_avr = 15.5; T_max = 19;
October: T_min = 9; T_avr = 11.5; T_max = 14;
November: T_min = 6; T_avr = 8.0; T_max = 10;
December: T_min = 3; T_avr = 5.0; T_max = 7;