Tag: required

The goal of the function is to find out how to get from one angle to another. It's about two things: the amount you have to move around and the direction (+ means turn right, – means turn left). The angle does not have to move more than 180 degrees. The function is rather short. I wanted to avoid using and triggering functions or pi. I want this as fast as possible while maintaining readability.

import pandas as pd
import numpy as np

def get_wind_dir_difd(dir_1, dir_2):
    """
    Figures out the shortest way to get from dir_1 to dir_2. Positive nunber go clockwise, negative numbers go counter clockwise.
    NOTE: The direction 0 and 360 are the same.
    :param dir_1: int. The direction of the first wind.
    :param dir_2: The direction of the second wind.
    :return: int. The what to add (can be a negative number too) to the first wind dir to get to the second wind dir.
    """
    diff = dir_2 - dir_1

    if diff > 180:  # the highest diff can be is 180
        diff = 360 - diff

    elif diff < -180:  # the lowest diff can be is -180
        diff = 360 + diff

    if dir_2 > dir_1 and (dir_2 - dir_1 > 180):  # ensures the correct sign is used when dir_2 is larger and the difference betwene the two is more than 180, EX 10, 310 or 40, 360
        diff = -diff

    return diff

# IGNORE WHAT IS BELOW, THAT IS JUST TO TEST

get_wind_dir_dif_vec = np.vectorize(get_wind_dir_difd)

df = pd.read_csv('test.csv')

df('diff') = get_wind_dir_dif_vec(df('val1'), df('val2'))

for i in range(len(df)):
    row = df.iloc(i)
    correct_or_not = row('diff') == row('what_diff_should_be')
    if correct_or_not:
        correct_or_not = ''
    else:
        correct_or_not = 'X'
    df.set_value(i, ' bad_answer ', correct_or_not)

print(df)

To give you a better overview of the program

    val1  val2  diff  what_diff_should_be  bad_answer 
0    120    30   -90                  -90             
1    340    20    40                   40             
2     20   340   -40                  -40             
3    310    10    60                   60             
4     10   310   -60                  -60             
5      0   300   -60                  -60             
6    300     0    60                   60             
7    190   180   -10                  -10             
8    180   190    10                   10             
9    200   220    20                   20             
10   220   200   -20                  -20             
11    10   190   180                  180             
12   360     0     0                    0             
13     0   360     0                    0             
14   340    20    40                   40             
15   350     0    10                   10             
16   350   360    10                   10             
17    40   360   -40                  -40             
18   180     0  -180                 -180             
19     0   180   180                  180             

This is the CSV I tested it on.

val1,val2,diff,what_diff_should_be
120,30,,-90
340,20,,40
20,340,,-40
310,10,,60
10,310,,-60
0,300,,-60
300,0,,60
190,180,,-10
180,190,,10
200,220,,20
220,200,,-20
10,190,,180
360,0,,0
0,360,,0
340,20,,40
350,0,,10
350,360,,10
40,360,,-40
180,0,,-180
0,180,,180