参考计算列表的部分（Python）

Question

I have to calculate the distance between a set of points that are given and multiple points which come from a list.

an example of a line from the list is;

['14', '"Name of place"', '-31.000', '115.000']

As the calc distance function takes four parameters I put the two given points in then then long and lat values of the list.

My understanding was to do this I could simply refer to the list aka 'List' then which part of each line I want to access aka 2 and 3

        User_E = raw_input("First enter your longitude(easting) value")
        User_N = raw_input("Now enter your latitude(northing) value")
        Radius = raw_input("Now enter a search radius in kilometres")
        for lines in ListOfLandmarks:
            CalculateDistance( User_N, User_E, ListOfLandmarks[2], ListOfLandmarks[3] )

when I run the program I receive the below error:

TypeError: unsupported operand type(s) for -: 'str' and 'list'

Iv'e tried to use int and float to identify them as numbers but they produce the following:

TypeError: int() argument must be a string or a number, not 'list'

TypeError: float() argument must be a string or a number

def CalculateDistance( latOne, lonOne, latTwo, lonTwo ):
DISTANCE_CONSTANT = 111120.0
coLat = math.fabs(lonOne - lonTwo)
alpha = 90 - latTwo
beta  = 90 - latOne

cosAlpha = math.cos(math.radians(alpha))
cosBeta  = math.cos(math.radians(beta))
sinAlpha = math.sin(math.radians(alpha))
sinBeta  = math.sin(math.radians(beta))
cosC     = math.cos(math.radians(coLat))

cos_of_angle_a = (cosAlpha * cosBeta)
cos_of_angle_b = (sinAlpha * sinBeta * cosC)
cos_of_angle_c = cos_of_angle_a + cos_of_angle_b
angle          = math.degrees(math.acos(cos_of_angle_c))
Distance       = angle * DISTANCE_CONSTANT
return Distance

Just wondering where I am going wrong, cheers!

Answer 1

Skipping the conversion issues (as you store your coordinates as strings instead of floats)

for lines in ListOfLandmarks:
        CalculateDistance( User_N, User_E, ListOfLandmarks[2], ListOfLandmarks[3] )

should be

for lines in ListOfLandmarks:
        CalculateDistance( User_N, User_E, lines[2], lines[3] )

As you ask for distance to the particular landmark that you iterate through, ListOfLandmarks[2] is a second landmark (so a list which your interpreter does not know how to compare/use in the float context), while the first coordinate of the current landmark is lines[2]