定义一个函数画棱形

def diamond(height):

"""Return a string resembling a diamond of specified height (measured in lines).

height must be an even integer.

"""

L=[]

line=''

s='/'

bs='\\'

for i in range(1,int(height/2+1)):

a=line.rjust(i,s).ljust(i*2,bs).center(height)

L.append(a)

for j in range(int(height/2),0,-1):

b=line.rjust(int(j),bs).ljust(j*2,s).center(height)

L.append(b)

for item in L:

line+=item+'\n'

return line

def diamond(height):

s = ''

# The characters currently being used to build the left and right half of

# the diamond, respectively. (We need to escape the backslash with another

# backslash so Python knows we mean a literal "\" character.)

l, r = '/', '\\'

# The "radius" of the diamond (used in lots of calculations)

rad = height // 2

for row in range(height):

# The first time we pass the halfway mark, swap the left and right characters

if row == rad:

l, r = r, l

if row < rad:

# For the first row, use one left character and one right. For

# the second row, use two of each, and so on...

nchars = row+1

else:

# Until we go past the midpoint. Then we start counting back down to 1.

nchars = height - row

left = (l * nchars).rjust(rad)

right = (r * nchars).ljust(rad)

s += left + right + '\n'

# Trim the last newline - we want every line to end with a newline character

# *except* the last

return s[:-1]