Unable to understand TypeError

Can someone please explain why I'm getting this error? My code:

def x(n):
    if n == 1: n = 4
    elif n == 2: n = 3
    elif n == 3: n = 2
    elif n == 4: n = 1
    return n

def y(n):
    if n == 1: n = 2
    elif n == 2: n = 1
    elif n == 3: n = 4
    elif n == 4: n = 3
    return n

def query_x(i, j, quadrants):
    quadrants[i-1:j] = map(x, quadrants[i-1:j])

def query_y(i, j, quadrants):
    quadrants[i-1:j] = map(y, quadrants[i-1:j])

def query_c(i, j, quadrants):
    count = [quadrants[i-1:j].count(n) for n in range(1,5)]
    print "%d %d %d %d" % (count[0], count[1], count[2], count[3])

def process_queries(queries, quadrants):

    for query in queries:
        if   query[0] == "X": query_x(query[1], query[2], quadrants)
        elif query[0] == "Y": query_y(query[1], query[2], quadrants)
        elif query[0] == "C": query_c(query[1], query[2], quadrants)

if __name__ == "__main__":

    N = int(raw_input())

    quadrants = []
    for i in xrange(N):
        pair = map(int, raw_input().split())
        x, y = pair

        if   x > 0 and y > 0: quadrants.append(1)
        elif x < 0 and y > 0: quadrants.append(2)
        elif x < 0 and y < 0: quadrants.append(3)
        elif x > 0 and y < 0: quadrants.append(4)

    Q = int(raw_input())

    queries = []
    for i in xrange(Q):
        query = raw_input().split()
        queries.append([query[0], int(query[1]), int(query[2])])

    process_queries(queries, quadrants)

Output:

4
1 1
-1 1
-1 -1
1 -1
5
C 1 4
X 2 4
C 3 4
Y 1 2
C 1 3
1 1 1 1
Traceback (most recent call last):
  File "QuadrantQueries_dev.py", line 53, in <module>
      process_queries(queries, quadrants)
  File "QuadrantQueries_dev.py", line 28, in process_queries开发者_JS百科
      if   query[0] == "X": query_x(query[1], query[2], quadrants)
  File "QuadrantQueries_dev.py", line 16, in query_x
      quadrants[i-1:j] = map(x, quadrants[i-1:j])
  TypeError: 'int' object is not callable

---

pair = map(int, raw_input().split())
x, y = pair

On line 39 you are redefining the x and y objects to be integers. x and y no longer reference the functions that you defined at the top. Your "main" block of code is not a separate function scope you are still at the global namespace.

http://docs.python.org/tutorial/classes.html#python-scopes-and-namespaces

---

I think your code could use some improvements. I decided to rewrite the whole thing. Perhaps you will like some of my changes.

First, we can use dictionaries to handle the remapping of quadrant numbers. Second, we can make a helper function to compute the quadrant numbers. Then we can build the list of quadrant numbers and process it. Instead of reading queries, building a list of them, and then processing them later, this code just reads the queries and processes them.

dmapx = {1:4, 2:3, 3:2, 4:1}
dmapy = {1:2, 2:1, 3:4, 4:3}

def quadnum(x, y):
    if x >= 0 and y >= 0:
        return 1
    elif x < 0 and y >= 0:
        return 2
    elif x < 0 and y < 0:
        return 3
    else:
        return 4


def rewrite_x(quadrants, i, j):
    quadrants[i-1:j] = [dmapx[x] for x in quadrants[i-1:j]]

def rewrite_y(quadrants, i, j):
    quadrants[i-1:j] = [dmapy[y] for y in quadrants[i-1:j]]

def print_counts(quadrants, i, j):
    count = [quadrants[i-1:j].count(n) for n in range(1,5)]
    print "%d %d %d %d" % tuple(count)

def parse_quadrants():
    n = int(raw_input())
    for _ in xrange(n):
        yield [int(s) for s in raw_input().split()]

def parse_queries():
    n = int(raw_input())
    for _ in xrange(n):
        code, i, j = raw_input().split()
        i = int(i)
        j = int(j)
        yield (code, i, j)

if __name__ == "__main__":
    # parse quadrants from input, and build list of quadrant numbers
    quadrants = [quadnum(x, y) for x, y in parse_quadrants()]

    # parse and handle queries
    for code, i, j in parse_queries():
        if code == "X":
            rewrite_x(quadrants, i, j)
        elif code == "Y":
            rewrite_y(quadrants, i, j)
        elif code == "C":
            print_counts(quadrants, i, j)
        else
            raise ValueError, "bad code: %s" % str(code)