python - 删除键时字典中的键错误

Question

我正在尝试对字符串进行计数，我想删除值为 1 和 2 的键。我可以使用以下脚本成功地对字符串进行计数。如果我将 if 循环添加到字典中，当我尝试打印它时它会抛出 Key error 'd'。

s = "aaabbbd"
def check_freq(s):
     freq = {}
     for c in s:
        freq[c] = s.count(c)
     for w in sorted(freq, key=freq.get, reverse=True):
         if freq[w] == 1:
             del freq[w]
             print (w, freq[w])

check_freq(s)

错误如下

File "<ipython-input-60-a79c71ac1b31>", line 10, in check_freq
    print (w, freq[w])

KeyError: 'd'

预期输出

{'a': 3, 'b': 3}

Answer 1

如果删除 key ，如何打印？因为 key 已删除，所以它会引发 KeyError，因为 key 不再存在。删除的时候加个continue就可以了。

s = "aaabbbd"
def check_freq(s):
    freq = {}
    for c in s:
        freq[c] = s.count(c)
    for w in sorted(freq, key=freq.get, reverse=True):
        if freq[w] == 1:
            del freq[w]
            continue
        print (w, freq[w])
    return freq
result = check_freq(s)

>a 3
b 3

result 
> {'a': 3, 'b': 3}