CODEWITHSUNDEEP
pythondictionarycoordinates
user1718623
user1718623

Reputation: 13

finding coordinates in python

so i have this assignment where i'm given a "map"

island = \
['     /---------\       ',
 '     |     x    \      ',
 '     /           \--\  ',
 '    /   x            | ',
 '    |         x      | ',
 '     \               \ ',
 '      \  x  /\/\     / ',
 '       \---/    \   |  ',
 '                /--/   ']

Write a program that counts the number of treasures on the island (x marks the spot) and creates a list of coordinates, e.g. [(1,11), ...] ((1,11) is the actual location of the top treasure in the example) and then prints out a report in the form: There are 3 treasures. There is a treasure at (1,11). There is a treasure at .... Hint: start with a (very short) expression for the symbol in the ith row and the jth column.

Write a program that calculates the length of the coastline. Assume that an '-' and a '|' are 1 mile, and a '\', '/' is 1.4 miles. (This is only a very rough estimate, for many reasons, some of them mathematical).

i'm not even sure where to begin here....can anybody help me out or at the very least point me in the right direction?

Upvotes: 0

Views: 6047

Answers (9)

melvin m
melvin m

Reputation: 1

I am a beginner to python and the problem is quite interesting, my solution to this problem is as follows: thanks to @Eric for giving an idea for start

island = \
['     /---------\       ',
 '     |     x    \      ',
 '     /           \--\  ',
 '    /   x            | ',
 '    |         x      | ',
 '     \               \ ',
 '      \  x  /\/\     / ',
 '       \---/    \   |  ',
 '                /--/   ']
Distance={
    "-":1.0,
    "|":1,
    "\\":1.4,
    "/":1.4
}
Treasure_Location = []
Miles = []
for row, line in enumerate(island):
    #print(row, line)

    for column, cell in enumerate(line):
        if cell== "x":
            Treasure_Location.append((row, column))

        if cell in Distance:
            z=Distance.get(cell)
            Miles.append(z)

Total_miles= sum(Miles)

print ("Co-ordinates of the Treasure in the Island are:\n")
print("\nTreasure 1: " + str(Treasure_Location[0]))
print("\nTreasure 2: " + str(Treasure_Location[1]))
print("\nTreasure 3: " + str(Treasure_Location[2]))
print("\nTreasure 4: " + str(Treasure_Location[3]))
print("\nThe length of the Coastal line is:"+str(Total_miles))

Upvotes: 0

user1701047
user1701047

Reputation: 747

2 dimensional grids are pretty easily represented in some sort of an array. Create an array that stores all of your grid in a way you understand how to lookup what coordinate x,y is in that array.

Check for all the treasures by iterating through the array's indexes.

The coastline is just a perimeter measurement but it's represented much simpler, every character you find is equivalent to some number. Just run a loop again, looking for these character and when you encounter them, increase some running sum of the coastline.

*You could do all of this in a single loop or in other simple ways...best way for you to do it is to break it up into pieces so you understand how to do this.

Upvotes: 0

Eric
Eric

Reputation: 97571

For the sake of posting a (semi-pythonic) solution:

# reads as it means - coords where the cell is "x"
treasure_coords = [
    (x, y) for y, row in enumerate(island)
           for x, c in enumerate(row)
           if c == 'x'
]

# slightly more cryptic
coast_length = sum(
    1   if c in '-|'  else
    1.4 if c in '/\\' else
    0
    for c in ''.join(island)
)

Upvotes: 1

Steven Rumbalski
Steven Rumbalski

Reputation: 45542

Since people are posting complete solutions, here is one that is Pythonic but not advanced.

segment_lengths = {'\\':1.4,'/':1.4,'-':1,'|':1}
coast_len = 0
treasure_coords = []
for y, line in enumerate(island):
    for x, c in enumerate(line):
        coast_len += segment_lengths.get(c, 0)
        if c == 'x':
            treasure_coords.append((y, x))
print len(treasure_coords), 'treasures found at', treasure_coords
print 'island coast length is', coast_len

Prints:

4 treasures found at [(1, 11), (3, 8), (4, 14), (6, 9)]
island coast length is 49.0

edit: J.F. Sebastian offers an if-elif based solution:

coast_length = 0
treasure_coords = []
for y, row in enumerate(island):
    for x, c in enumerate(row):
        if c in r'\/':
            coast_length += 1.4
        elif c in '-|':
            coast_length += 1
        elif c == 'x':
            treasure_coords.append((y, x))

print("There are %d treasures." % (len(treasure_coords),))
for y, x in treasure_coords:
    print("There is a treasure at (%2d, %2d)." % (y, x))
print("The length of the coastline is %.1f." % (coast_length,))

Upvotes: 1

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 250931

Pythonic solution for length of coastline part:

In [144]: strs
Out[144]: 
['     /---------\\       ',
 '     |     x    \\      ',
 '     /           \\--\\  ',
 '    /   x            | ',
 '    |         x      | ',
 '     \\               \\ ',
 '      \\  x  /\\/\\     / ',
 '       \\---/    \\   |  ',
 '                /--/   ']

In [145]: dic={'\\':1.4,'/':1.4,'-':1,'|':1}

In [146]: sum(dic.get(y,0) for x in strs for y in x)
Out[146]: 48.999999999999979

or 

In [149]: sum(map(lambda x:dic.get(x,0),chain(*strs)))
Out[149]: 48.999999999999979

or (As suggested by Eric):

In [197]: sum(dic.get(x,0) for x in chain(*strs))
Out[197]: 48.999999999999979

for co-ordinates:

In [185]: [(i,m.start()) for i,x in enumerate(strs) for m in re.finditer('x',x)]
Out[185]: [(1, 11), (3, 8), (4, 14), (6, 9)]

Upvotes: 0

Timidger
Timidger

Reputation: 1209

Since each line is a value in a list, you can use a simple 'in' check to see if there is a treasure.

 for line in island:
     if 'x' in island[line]:
         print '%d,%d' %line,island[line].index('x')

Easy way to get your cords.

Upvotes: -1

D Read
D Read

Reputation: 3224

To get the length of the coastline, you just need to count the instances of each coast character.

>>> from itertools import groupby
>>> dict([(k, len(list(g))) for k, g in groupby(sorted(''.join(island)))])
{' ': 162, '-': 16, '/': 9, '\\': 11, 'x': 4, '|': 5}

Then you can add them up:

>>> char_counts = dict([(k, len(list(g))) for k, g in groupby(sorted(''.join(island)))])
>>> char_counts['-'] + char_counts['|'] + 1.4 * (char_counts['/'] + char_counts['\\'])
49.0

Upvotes: 0

fh_spitfire
fh_spitfire

Reputation: 77

Very simple way to do that would be just iterate over every single char (recording the current col/row_ and check it for being 'x' or one of the coast symbols. Like that:

length = 0.0
x = 0
y = 0
for line in island:
    x += 1
    y = 0
    for char in line:
        y += 1
        if char == 'x': print 'There is a treasure at (%d,%d)' % (x, y)
        elif char in ('-', '|'):
            length += 1
        elif char in ('\\', '/'):
            length += 1.4
print 'Coast length is', length

Of course it doesn't check for treasures in the sea, coast integrity, etc.

Upvotes: 0

Eric
Eric

Reputation: 97571

First thing you'll want to do is iterate over the array

for column, line in enumerate(island):
    print column, line

That gives you

0      /---------\       
1      |     x    \      
2      /           \--\  
3     /   x            | 
4     |         x      | 
5      \               \ 
6       \  x  /\/\     / 
7        \---/    \   |  
8                 /--/

Ok, so how about iterating horizontally over each row? Exactly the same:

for column, line in enumerate(island):
    for row, cell in enumerate(line):
        print "entry at", row, column, "is", cell

Warning: gives long output!

That should be enough to get you started

Upvotes: 7

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