用列表生成帕斯卡尔三角形

Question

我的作业是用列表来制作帕斯卡三角形。我会接收用户输入的三角形高度，然后从这个高度开始构建三角形。我有一段伪代码，但我不知道如何实现最后的“Else”部分，那里提到要找到“A”的值，它在三角形上面一行，往回一列；还有“B”的值，它在三角形上面一行，列数不变。

这是我的伪代码：

https://i.stack.imgur.com/aFwkT.jpg.

谢谢！

代码：

def pascalsTriangle():
height = int(input("Enter height of triangle:"))
t_List = []
for R in t_List(0,height+1):
    n_List = []
    if R == 0:
        n_List = [1]
    elif R == 1:
        n_List == [1,1]
    else:
        for C in R:
            if C == 0:
                n_List.append(1)
            elif C == R:
                n_List.append(1)
            else:
                A = t_List()

Answer 1

这个应该对你有用：

def my_pattern(n): 
    tree = [[1]] #first row is always just 1
    for x in range(1, n): #for every other row:
        m = [1] #it always starts with 1
        for y in range(1, x): #for all the others:
            m.append(tree[x-1][y-1] + tree[x-1][y]) #work out what the number is
        m.append(1) #it always ends in 1
        tree.append(m) #add the row on
    return tree

Answer 2

你可以为这个三角形创建一个列表，里面包含多个列表，每个列表代表三角形的一行。这些行可以通过递归的方式生成。

height = int(input())

def pascal(h, nums): # Height and array of current triangle
  if h == 1: # finished!
    return nums

  next_row = [1]# Start row

  # Iterate through the last row
  for i in range(len(nums[-1]) - 1): 
    # Append each item in the last row addded to the item on the right
    next_row.append(nums[-1][i] + nums[-1][i + 1])

  next_row.append(1) # End row

  nums.append(next_row) # Add row to triangle

  return pascal (h - 1, nums) # Repeat at next row


# Start the recursion with the top of the triangle
triangle = pascal(height, [[1]]) 
print triangle

Answer 3

你可以创建一个列表的列表。

def pascalsTriangle():
  height = int(input("Enter height of triangle: "))
  triangle = []
  row = []
  prev_row = []
  for i in xrange(0, height + 1):
    row = [j > 0 and j < i - 1 and i > 2 and prev_row[j-1] + prev_row[j] or 1 for j in xrange(0, i)]
    prev_row = row
    triangle += [row]
  return triangle[1:]

比如说：

 Enter height of triangle: 5
 [[1], [1, 1], [1, 2, 1], [1, 3, 3, 1], [1, 4, 6, 4, 1]]

Answer 4

def pascal_triangle(height):
    if height < 0 : return
    # height = 0
    T = [[1]]
    # loop for the next r = [1:height+1]
    for R in range(1, height + 2):
        # c == 0
        N = [1]
        # caculate [1:r) (exclude r itself)
        for C in range(1, R):
            a = T[R - 1][C - 1]
            b = T[R - 1][C]
            # c = a + b
            N.append(a + b)
        # c == r
        N.append(1)
        T.append(N)
    # print each R, from [0, height+1], total row is height+2
    for R in T:
        # i want to a pyramid, but the last row will
        # still have a single leading space
        print ' ' * (height - len(R) + 2),
        for C in R:
            print C,
        # new line
        print


if __name__ == '__main__':
    import sys
    pascal_triangle(int(sys.argv[1]))

$ python /tmp/test.py 4
      1
     1 1
    1 2 1
   1 3 3 1
  1 4 6 4 1
 1 5 10 10 5 1

当然可以！请把你想要翻译的内容发给我，我会帮你用简单易懂的语言解释清楚。

Answer 5

from functools import reduce

def pascal (level, acc = None):
    if not acc: acc = [[1]]
    if level == 1: return acc
    acc.append ( [1] + [a + b for a, b in zip (acc [-1], acc [-1] [1:] ) ] + [1] )
    return pascal (level - 1, acc)

print (pascal (6) )

当然可以！不过你没有提供具体的内容。请把你想要翻译的StackOverflow内容发给我，我会帮你用简单易懂的语言解释清楚。