Question

我有一个包含大量数据的大型列表，这些数据是从csv文件中读取的。为简单起见，我将为您提供一个虚拟列表，其中包含的数据要少得多。

list1 = ['foo', 'bar', 'bob', 'jess', 'google', 'alphabet']

我想找到列表中字符串的平均长度。我目前正在这样做：

all_lengths = []
num_of_strings = len(list1)

for item in list1:
    string_size = len(item)
    all_lengths.append(string_size)
    total_size = sum(all_lengths)
ave_size = float(total_size) / float(num_of_strings)

问题在于，因为真实的清单太大，所以需要花费相当长的时间来执行此操作。

是否有更优化或更优雅的方式来执行此操作。

另外，对于它的价值，使用Python2.7

Answer 1

total_avg = sum( map(len, strings) ) / len(strings)

代码中的问题出在以下代码行中： total_size = sum(all_lengths) 没有必要在循环的每个循环中计算这个。循环后更好地完成这个。

Answer 2

我能想到的最简单的方法是：

list1 = ['foo', 'bar', 'bob', 'jess', 'google', 'alphabet']
total = 0
for i in list1:
    total += len(i)
ave_size = float(total) / float(len(list1))
print(ave_size)

Answer 3

在循环中的每个点同时计算平均值和总数相当容易，因此您也可以显示进度：

total = 0
items = 0
average = 0.
for item in very_long_list:
    items += 1
    total += len(item)
    average = float(total) / items
    print 'Processed items: %d with a total of %d and an average length of %.1f' % (
        items,
        total,
        average,
    )

Answer 4

只使用均值和理解：

holder.view.setOnClickListener{
    val curValue = holder.adapterPosition
    val selectedValue = stations[curValue].name

    //something should be done here to change button's color

    (context as MainActivity).updateButtonColor(HEX_COLOR)
}

Answer 5

我想您可以将字符串循环连接成一个大字符串，以检查所有项目的长度。

list1 = ['foo', 'bar', 'bob', 'jess', 'google', 'alphabet']

combined_string = ''
for item in list1:
    combined_string += item

print(float(len(combined_string)) / float(len(list1)))

Answer 6

使用纯Python和列表理解：

list_of_strings = ["My cat ran across the street",
                   "I love my blue shirt",
                   "Sir, would you like another coffee?",
                   "Mountain",
                   "Car",
                   "I wish in school there had been a class where all you do is solve puzzles the entire class. Instead of taking trigonometry, which I 100% forget."]

# Average length of strings
avg_string_length = sum([len(i) for i in list_of_strings])/len(list_of_strings)
avg_string_length

>>> 39.666666666666664

# Round it out
round(avg_string_length)

>>> 40

查找列表中字符串的平均长度

6 个答案: