python统计英文首字母出现的次数

使用python解析有道词典导出的xml格式单词，统计各个首字母出现的次数，并按次数由多到少进行排序

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相关实现

导出的xml格式如下

<wordbook>
    <item>    
        <word>portion</word>
        <trans><![CDATA[n. 部分；一份；命运vt. 分配；给…嫁妆]]></trans>
        <phonetic><![CDATA[['pɔːʃ(ə)n]]]></phonetic>
        <tags></tags>
        <progress>2</progress>
    </item>
</wordbook>

使用python3自带的xml解析器进行解析，使用字典进行保存统计结果

import time
import xml.etree.ElementTree as et

# get all word
def get_all_word(uri):
    tree = et.parse(uri)
    root = tree.getroot()
    return root.findall('./item/word')

# calculate the first letter frequency of words
def cal_aleph(word_list):
    # define dwords to save first letter count
    dwords = {}
    for cword in word_list:
        letter = cword.text.strip()[0].lower()
        # judge the letter is english letter
        echar = ord(letter)
        if(echar >= 97 and echar <= 122):
            try:
                dwords[letter] += 1
            except KeyError:
                dwords[letter] = 1;
    # order by count desc
    dwords = sorted(dwords.items(), key=lambda line:line[1], reverse=True)
    return dwords

if __name__ == '__main__':
    start_time = time.time()
    word_list = get_all_word(r'd:\pyzone\youdao.xml')
    result = cal_aleph(word_list)
    for row in result:
        print("%s : %d"%(row[0], row[1]))
    end_time = time.time()
    print('Costed time: ' + str((end_time - start_time)) + 's')

统计结果如下：

回顾

• 使用xml.etree.ElementTree的parse解析指定路径的xml文件，root.findall查找指定节点
• sorted方法对列表进行排序
• '中文'.isalpha() 结果为True