如何从字符串中删除前导和尾随空格

string = "  Hello, World!  "
trimmed_string = string.strip()
print(trimmed_string)  # 输出：Hello, World!

import re

string = "  Hello, World!  "
trimmed_string = re.sub(r'^\s+|\s+$', '', string)
print(trimmed_string)  # 输出：Hello, World!

string = "  Hello, World!  "
trimmed_string = ""
start_index = 0
end_index = len(string) - 1

# 删除前导空格
while start_index <= end_index and string[start_index] == ' ':
    start_index += 1

# 删除尾随空格
while end_index >= start_index and string[end_index] == ' ':
    end_index -= 1

# 构建修剪后的字符串
for i in range(start_index, end_index + 1):
    trimmed_string += string[i]

print(trimmed_string)  # 输出：Hello, World!