如何统计文本中不含空格和数字的字母出现频率？

import re
from collections import Counter

def count_letter_frequency(text):
    # 使用正则表达式去除空格和数字
    cleaned_text = re.sub(r'[^a-zA-Z]', '', text)
    
    # 统计每个字母的出现次数
    letter_counts = Counter(cleaned_text.lower())
    
    # 计算总字母数
    total_letters = sum(letter_counts.values())
    
    # 计算每个字母的频率
    letter_frequencies = {letter: count / total_letters for letter, count in letter_counts.items()}
    
    return letter_frequencies

# 示例文本
text = "Hello, World! 123"
frequencies = count_letter_frequency(text)
print(frequencies)