Python中如何让输出的帕斯卡三角列表居中显示？

我编写了Python代码，可根据指定的三角层数、首行数字数量及具体数字生成帕斯卡三角，但打印各列表时无法实现居中显示，导致输出形态不呈三角状。尝试使用{:^80}格式化方式但未生效，原代码如下：

import math

print("This code is used to calculate pascals triangle starting from any given number and giving a list as long as needed")

layers = int(input("Enter how many layers you want to calculate (Works best if less than 20):"))
num_amount = int(input("Enter how many numbers you want in the first line :"))

pascal_nums = []
for i in range(0, num_amount):
    cur_num = int(input("Enter number here :"))
    pascal_nums.append(cur_num)
pascal_nums.insert(0, 1)
pascal_nums.append(1)
j = 0
while j <= layers:
    print(" ", end="")
    j += 1
print(*pascal_nums)

for i in range(0, layers):
    for i in range(0, len(pascal_nums)-1):
        temp_num = pascal_nums[i] + pascal_nums[i + 1]
        pascal_nums.remove(pascal_nums[i])
        pascal_nums.insert(i, temp_num)
    pascal_nums.insert(0, 1)
    j = i
    while j <= layers:
        print(" ", end="")
        j += 1
    print(*pascal_nums)

问题分析 #

原代码的核心问题：

• 直接打印列表元素时未统一数字宽度，数字位数变化（如从个位数变为两位数）会破坏对齐。
• 前置空格的计算逻辑错误，固定空格数无法适配不同长度的行，且缩进方向与三角形态需求相反。
• 生成下一行时直接修改原列表，导致索引混乱，同时逻辑冗余。

修复方案 #

修改思路：

1. 统一每个数字的显示宽度，确保对齐一致性。
2. 利用字符串center方法实现自动居中，无需手动计算空格。
3. 重构行生成逻辑，通过创建新列表避免索引错误。

修改后的代码：

# 可根据需求调整数字显示宽度和整体总宽度
NUM_WIDTH = 4
TOTAL_WIDTH = 80

print("This code is used to calculate pascals triangle starting from any given number and giving a list as long as needed")

layers = int(input("Enter how many layers you want to calculate (Works best if less than 20):"))
num_amount = int(input("Enter how many numbers you want in the first line :"))

# 初始化首行自定义数字
pascal_nums = []
for _ in range(num_amount):
    cur_num = int(input("Enter number here :"))
    pascal_nums.append(cur_num)
# 拼接首尾的1，形成完整首行
current_row = [1] + pascal_nums + [1]

# 格式化并居中打印首行
row_str = "".join(f"{num:{NUM_WIDTH}d}" for num in current_row)
print(row_str.center(TOTAL_WIDTH))

# 生成并打印后续行
for _ in range(layers):
    next_row = [1]
    # 计算下一行的中间数字
    for i in range(len(current_row)-1):
        next_row.append(current_row[i] + current_row[i+1])
    next_row.append(1)
    current_row = next_row
    # 居中打印当前行
    row_str = "".join(f"{num:{NUM_WIDTH}d}" for num in current_row)
    print(row_str.center(TOTAL_WIDTH))

关键说明 #

• NUM_WIDTH：控制每个数字占用的字符宽度，确保不同位数的数字对齐整齐。
• row_str.center(TOTAL_WIDTH)：自动计算并添加左右空格，实现行内容的居中显示。
• 新行生成逻辑：通过创建next_row存储下一行数据，避免直接修改原列表导致的索引混乱，逻辑更清晰可靠。

内容的提问来源于stack exchange，提问作者Adam Hutton