Same if statement in collision detection doesn't work w/ different variables

Question

I'm trying to detect if the player has hit the block, and if so, stopping them of course (eg if it hits a wall on the left it can't move left). So it works fine, I've done the collision for up and down, but for some reason when I go on to do the collision for the left side (the last if statement) the player is able to just move through the block and I can't figure out why, because the if statement is basically the same.

FYI: pX is the x co-ordinate of the player, pY is the y co-ordinate of the player, XnY[1] is the y co-ordinate of the block, XnY[0] is the x co - ordinate of the block, playerSize is it's a square, so 50x50

    level =  ["W","W","W","W","W","W","W","W","W","W","W","W",
              "N","N","N","N","N","N","N","N","N","N","N","N","L",
              "N","N","N","N","N","N","N","N","N","N","N","N","L",
              "N","N","N","N","N","N","N","N","N","N","N","N","L",                                       
              "N","N","N","N","N","N","N","N","N","N","N","N","L",                                     
              "N","N","N","N","N","N","P","N","N","N","N","N","L",
              "N","N","N","N","N","N","N","N","N","N","N","N","L",
              "N","N","N","N","N","N","N","N","N","N","N","N","L",
              "N","N","N","N","N","N","N","N","N","N","N","N","L",
              "N","N","N","N","N","N","N","N","N","N","N","N","L",
              "N","N","N","N","N","N","N","N","N","N","N","N","L","S"]    
blockXY = []

    for element in level:
        if element == "N":
             x += block_width
        if element == "L":                                              
             y += block_height
             x = 0
        if element == "P": 
            drawBlock(block_width,block_height,x,y)                
            blockXY.append(x)
            blockXY.append(y)
            if appendBlockXY:
                if len(collisionArray) > P_count:
                    del(collisionArray[P_count])
                    print(collisionArray)
                    appendBlockXY = False
                collisionArray.append(blockXY)
            blockXY = []
            x += block_width
        if element == "S":
            y = 0


for XnY in collisionArray

        if pX >= XnY[0] and pX <= XnY[0] + block_width or pX + playerSize >= XnY[0] and pX <= XnY[0] + block_width:

            if pY - block_height == XnY[1]:
                canMoveUp = False
                y_change = 0

        if pX >= XnY[0] and pX <= XnY[0] + block_width or pX + playerSize >= XnY[0] and pX <= XnY[0] + block_width:

            if XnY[1] - playerSize == pY:
                canMoveDown = False
                y_change = 0

        if pY >= XnY[1] and pY <= XnY[1] + block_height or pY +  playerSize >= XnY[1] and pY + playerSize <= XnY[1] + block_height:

            if pX - block_width == XnY[0]:
                canMoveLeft = False
                y_change = 0

Answer 1

I got it working! It was a silly mistake on my part, instead of writing y_change = 0 it should have been x_change = 0. Ooops!