编写程序，统计字符串中每个字符出现的次数，并计算所占百分比。（利用字典的get函数 和Counter函数分别实现) import string xstr=string.digits+string.asci_letters+string.punctuation

编写Python程序，你可以使用`collections.Counter`函数轻松统计字符串中每个字符及其出现次数，以及计算所占百分比。这里有两个方法，一个是直接使用`Counter`，另一个是结合`get`函数。

**方法一：使用Counter**

from collections import Counter

xstr = string.digits + string.ascii_letters + string.punctuation
char_counts = Counter(xstr)

# 统计每个字符出现的次数
char_frequency = {char: count for char, count in char_counts.items()}

# 计算所占百分比
total_chars = sum(char_counts.values())
percentage_dict = {char: (count / total_chars) * 100 for char, count in char_frequency.items()}

print("每个字符的出现次数：", char_frequency)
print("每个字符的百分比：", percentage_dict)

**方法二：使用字典的get函数**

xstr = string.digits + string.ascii_letters + string.punctuation
char_frequency = {}
for char in xstr:
    char_frequency[char] = char_frequency.get(char, 0) + 1  # 如果键不存在，返回默认值0并加1

# 计算总字符数
total_chars = len(xstr)

# 转换为百分比
percentage_dict = {char: (freq / total_chars) * 100 for char, freq in char_frequency.items()}

print("每个字符的出现次数：", char_frequency)
print("每个字符的百分比：", percentage_dict)