使用 for 循环在 python 3+ 中的任何序列（列表、字符串、元组）中查找最频繁出现的字符

Question

问题： 10.最常见的字符编写一个程序，让用户输入一个字符串并显示该字符串中出现频率最高的字符。

这是给那些正在学习 "Starting out with Python" 第 9 章第 10 题的 cs 入门的答案。这个问题完全是用我在本书前面章节中学到的知识来回答的。我在这个网站上找不到任何类似的东西。这段代码对于像我这样的初学者来说可能还可以，所以我想分享一下。我知道这段代码看起来很糟糕，但它完成了工作......我在 Youtube 上找到的原始代码是用 Java 编写的，这里是 link：https://www.youtube.com/watch?v=dyWYLXKSPus 抱歉我的英语不好！）

string = "a11aawww1cccertgft1tzzzzzz1ggg111"
mylist_char = []
mylist_count = []
char = None
count = 0

for ch in string:
    temp_char = ch
    temp_count = 0
    for ch1 in string:
        if temp_char == ch1:
            temp_count += 1

    if temp_count > count:
        count = temp_count
        char = temp_char
mylist_char.append(char)
mylist_count.append(count)
for x in range(len(string)):
    for ch in string:
        temp_char = ch
        temp_count = 0
        for ch1 in string:
            if temp_char == ch1:
                temp_count += 1
        if temp_count == count and not(temp_char in mylist_char):
            mylist_char.append(temp_char)
            mylist_count.append(temp_count)
for x in range(len(mylist_char)):
    print("Character", mylist_char[x], "occurred", mylist_count[x], "times")

Answer 1

我对你的解决方案的问题是它看起来像 Java 在 Python 中重写——如果你想使用 Java，请使用 Java。如果您想使用 Python，请充分利用它所提供的功能。我在下面写了一个 "simple" 解决方案，它没有使用任何复杂的 Python 函数（例如，如果我真的在写它，我会使用 defaultdict 和理解）

string = "a11aawww1cccertgft1tzzzzzz1ggg111"

dictionary = {}

for character in list(string):
    if character in dictionary:
        dictionary[character] += 1
    else:
        dictionary[character] = 1

results = []

for key, value in dictionary.items():
    results.append((value, key))

for value, key in reversed(sorted(results)):
    print("Character", key, "occurred", value, "times")

Answer 2

# Most frequent Character

def most_frequent(a_string):

    # Create a string of symbols to exclude from counting.
    symbols = ' ,.-/?'
    characters = []
    characters_count = []

    # Check each individual character in the string.
    for ch in a_string:

        # Check that the character is not one of the symbols.
        if ch not in symbols:

            # If its not and we haven't seen it already, 
            # append it to the characters list.
            if ch not in characters:
                characters.append(ch)

                # And in the same index in the characters_count list
                characters_count.append(1)
            else:
                # If it is in the characters list, find its index
                # and add 1 to the same index at characters_count
                position = characters.index(ch)
                characters_count[position] = characters_count[position] + 1
    # find the largest value in the character_count list, it's index
    # and show the character at the same index at the characters list.
    print(characters[characters_count.index(max(characters_count))])

def main():
    # Get a string from the user.
    text = input('Give me some text and I will find you the most frequent character: ')
    most_frequent(text)

# Call main
main()

使用 for 循环在 python 3+ 中的任何序列（列表、字符串、元组）中查找最频繁出现的字符

Find Most Frequent Character(s) in any sequence(list, string, tuple) in python 3+ with for loop

python

sequences

character