用python打印1~20的整数实例讲解

i=1
while i<=20:
  print(i,end=' ') 
  if i%5==0:
    print(" ")
  i+=1

def NumberPrint(num):

  tail = " ".join([str(i) for i in range(num, 0, -1)])
  print(tail)

  for j in range(len(tail)):
    if tail[j] == " ":
      print(" " * (j + 1) + tail[j+1:])   
      # print(" " * j ,tail[j+1:])   # 以上另种答打印， j 是否 +1 ，主要是print函数中的 sep 参数
      # print("{:>{}}".format(tail[j + 1:], len(tail)))
NumberPrint(12)

def OutputFunc(n,flag=0):

  length = len(' '.join([str(i) for i in range(n, 0, -1)]))
  for i in range(n):
    if flag == 1: #正向打印
      output = " ".join(str(j) for j in range(i + 1, 0, -1))
    else: # 倒着打印
      output = ' '.join(str(j) for j in range(n - i, 0, -1))
    print("{:>{}}".format(output,length))

OutputFunc(12)

# 简化代码

def OutputFunc(n,flag=0):

  length = len(' '.join([str(i) for i in range(n, 0, -1)]))
  for i in range(n):
    if flag == 1:
      args = i+1 #正向打印
    else:
      args = n-i #倒着打印
    print("{:>{}}".format(' '.join(str(j) for j in range(args, 0, -1)), length))

OutputFunc(12)