如何将整数迭代加在一起

Question

This function prints a pyramid made of "*" and "&" characters. I want the program to print out the total number of "&" characters in the pyramid, so I used .count to count how many times "&" appears in each row. The problem is that I can't sum together the output from variable z to get the total time "&" appears in the pyramid. Any ideas?

import random
from random import choice
from random import randint

def pyramid():
    min_pyramid_size = 5
    max_pyramid_size = 10
    num_rows = random.randint(min_pyramid_size, max_pyramid_size)
    for i in range(num_rows):
        x = ''.join(str(random.choice('*&')) for j in range(2*i+1))
        print(' ' * (num_rows - i) + x)
        z = x.count('&')
        print(z)

pyramid()

UPDATE: I tried moving z out of the loop and it just prints the number of "&" in the last row.

import random
from random import choice
from random import randint

def pyramid():
    min_pyramid_size = 3
    max_pyramid_size = 5
    num_rows = random.randint(min_pyramid_size, max_pyramid_size)
    for i in range(num_rows):
        x = ''.join(str(random.choice('*&')) for j in range(2*i+1))
        print(' ' * (num_rows - i) + x)
    z = 0
    z += x.count('&')
    print(z)

pyramid()

Answer 1

Haven't run it, but you need a variable outside the for loop that will hold the total number of '&'s.

def pyramid():
    min_pyramid_size = 5
    max_pyramid_size = 10
    num_rows = random.randint(min_pyramid_size, max_pyramid_size)
    total_z = 0
    for i in range(num_rows):
        x = ''.join(str(random.choice('*&')) for j in range(2*i+1))
        print(' ' * (num_rows - i) + x)
        z = x.count('&')
        total_z = total_z + z
        print(z)

pyramid()

Answer 2

define z outside the scope of the for loop

z = 0

and use

z += x.count('&')

rather than

z = x.count('&')

Answer 3

Try this:-

import random
from random import choice
from random import randint

def pyramid():
    min_pyramid_size = 5
    max_pyramid_size = 10
    z = 0
    num_rows = random.randint(min_pyramid_size, max_pyramid_size)
    for i in range(num_rows):
        x = ''.join(str(random.choice('*&')) for j in range(2*i+1))
        print(' ' * (num_rows - i) + x)
        z = z + x.count('&')
    print(z)

pyramid()

Answer 4

Here's a more compact solution using a list comprehension:

def pyramid(min_size=5, max_size=10):
    N = randint(min_size, max_size)
    x = ''.join(' ' * (N-i) + ''.join(choice('*&') for j in range(2*i+1)) + '\n' for i in range(N))
    print(x)
    print(x.count('&'))

Demo:

>>>  pyramid()
         &
        &*&
       &**&*
      &&&**&*
     &***&&&&&
    &&&&*&&****
   &&&&*&***&&**
  *&&&&**&&&&&**&
 &*&***&*&&&*&&*&*

47

You could change the values of the minimum and maximum size of the pyramid by passing the appropriate arguments to the function, for example pyramid(min_size=8, max_size=12) .

Answer 5

You need to have two variables, one for the internal and one for the external count.

def pyramid():
  min_pyramid_size = 5
  max_pyramid_size = 10
  num_rows = random.randint(min_pyramid_size, max_pyramid_size)
  outer_z = 0
  for i in range(num_rows):
    x = ''.join(str(random.choice('*&')) for j in range(2*i+1))
    print(' ' * (num_rows - i) + x)
    inner_z = x.count('&')  # Alternatively calculate inner_z twice, but don't store it:
    print(inner_z)          # print(x.count('&'))
    outer_z += inner_z      # outer_z += x.count('&')
  print(outer_z)