在 Python 程序中，将十进制（denary）字符串转为字符，通常需要将字符串表示的数字解释为字符的 ASCII 或 Unicode 编码。
1、问题背景
在Python中，有人遇到一个denary字符串转字符的问题，代码如下：
# Set to true if testing. Will show lists that show the process.
testing = True
# Asks for the denary.
text = list(input('Enter the denary: '))
# Defining the list. 0 is there to allow the remover to work correctly.
doublesList = ['0']
# Split the numbers into doubles and append them to doublesList.
for i in range(len(text) - 1):
current_item = text[i]
next_item = text[i + 1]
doubles = current_item + next_item
doublesList.append(doubles)
if testing:
print('\nunedited:\n', doublesList,'\n')
# Remove unnecessary numbers.
for item in doublesList:
doublesList.remove(item)
if testing:
print('edited:\n', doublesList,'\n')
# Replace the numbers with their letters.
for item in doublesList:
if item == '01':
doublesList[doublesList.index('01')] = 'a'
elif item == '02':
doublesList[doublesList.index('02')] = 'b'
elif item == '03':
doublesList[doublesList.index('03')] = 'c'
elif item == '04':
doublesList[doublesList.index('04')] = 'd'
elif item == '05':
doublesList[doublesList.index('05')] = 'e'
elif item == '06':
doublesList[doublesList.index('06')] = 'f'
elif item == '07':
doublesList[doublesList.index('07')] = 'g'
elif item == '08':
doublesList[doublesList.index('08')] = 'h'
elif item == '09':
doublesList[doublesList.index('09')] = 'i'
elif item == '10':
doublesList[doublesList.index('10')] = 'j'
elif item == '11':
doublesList[doublesList.index('11')] = 'k'
elif item == '12':
doublesList[doublesList.index('12')] = 'l'
elif item == '13':
doublesList[doublesList.index('13')] = 'm'
elif item == '14':
doublesList[doublesList.index('14')] = 'n'
elif item == '15':
doublesList[doublesList.index('15')] = 'o'
elif item == '16':
doublesList[doublesList.index('16')] = 'p'
elif item == '17':
doublesList[doublesList.index('17')] = 'q'
elif item == '18':
doublesList[doublesList.index('18')] = 'r'
elif item == '19':
doublesList[doublesList.index('19')] = 's'
elif item == '20':
doublesList[doublesList.index('20')] = 't'
elif item == '21':
doublesList[doublesList.index('21')] = 'u'
elif item == '22':
doublesList[doublesList.index('22')] = 'v'
elif item == '23':
doublesList[doublesList.index('23')] = 'w'
elif item == '24':
doublesList[doublesList.index('24')] = 'x'
elif item == '25':
doublesList[doublesList.index('25')] = 'y'
elif item == '26':
doublesList[doublesList.index('26')] = 'z'
elif item == '27':
doublesList[doublesList.index('27')] = ' '
elif item == '28':
doublesList[doublesList.index('28')] = '.'
elif item == '29':
doublesList[doublesList.index('29')] = ''
elif item == '30':
doublesList[doublesList.index('30')] = '\n'
# Print the finished list as a string.
print(''.join(doublesList))
使用上面的代码，输入denary数字"2908051212152830132527140113052709192702150228"应该返回"hello.\nmy name is bob."。然而，结果是"hello.my nam\ne is bob."。
2、解决方案
要修复此代码，可以使用以下解决方案：
- 在循环中遍历输入，然后将它们成对组合在一起，并将其转换为整数。
- 过滤出代码表中不存在的字符。
- 使用map将整数转换为字符。
- 将字符列表连接成字符串并将其打印出来。
以下是修复后的代码：
characters = ' abcdefghijklmnopqrstuvwxyz . \n'
result = []
for pair in zip(text[::2], text[1::2]):
codepoint = int(''.join(pair))
if not (1 <= codepoint <= 30) or codepoint == 29: continue
result.append(characters[codepoint])
print(''.join(result))
这个修复程序适用于所有有效的denary字符串，并返回正确的字符串结果。
总结
- 使用
chr(int(num))进行十进制编码到字符的转换。 - 对输入的格式和范围进行验证，防止非法字符或超范围值。
- 通过通用函数支持不同的输入分隔符或格式。
- 添加异常处理，确保程序稳定运行。
这些方案可以适配大多数场景，根据需求灵活应用即可。
