Question

我有一个如下所示的csv：

someFile.csv

Header1 Header2 Header3
aa      aaa     a
bbbb    bbbbbb  aa

我想计算每列中的平均字符串长度，并创建结果的csv。这就是示例中的样子：

results.csv

Header1 Header2 Header3
3       4.5     1.5

我一直在尝试在Python中使用csv库，但没有成功。有没有简单的方法可以做到这一点？

Answer 1

您可以将zip行和map列移至len，并使用statistics.mean计算平均值：

import csv
from statistics import mean
with open('someFile.csv', 'r', newline='') as f, open('results.csv', 'w', newline='') as output:
    reader = csv.reader(f, delimiter=' ', skipinitialspace=True)
    headers = next(reader)
    writer = csv.writer(output, delimiter = ' ')
    writer.writerow(headers)
    writer.writerow([mean(map(len, col)) for col in zip(*reader)])

Answer 2

您可以尝试熊猫。如果您没有安装熊猫，请执行err1 + err2 + err3 + err4 + result来安装熊猫。

pip install pandas

希望这会有所帮助！

Answer 3

这是一个简单的代码。我提供了两个块，如果数据帧中没有null且存在Null。

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            <item name="searchIcon">@drawable/ic_search</item>
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            <item name="searchHintIcon">@drawable/ic_search</item>
        </style>

Answer 4

这不是最好的方法。还有其他方法可以快速执行此操作。但是，我确实认为这是一个非常简单明了且易于理解的示例，非常仓促地汇总在一起。我在您的示例中使用了它，并且可以正常工作。

import csv

# replace "yourusername" with your PC user name
input_file = 'C:/Users/yourusername/Desktop/someFile.csv' 
output_file = 'C:/Users/yourusername/Desktop/output.csv'

csv_file = open(input_file, newline='')  # opening csv file
info = list(csv.reader(csv_file))  # convert data in csv file to array/list
csv_file.close()

length = len(info[0])  # if you ever add more headers, this will account for it
avg_container = [0 for i in range(length)]  # creates empty array with zeros for each header
n = len(info[1:])  # for dividing by n to get average

# adding the lengths of all the items to one sum for each "column"
for k in info[1:]:
    for n,i in enumerate(k):
        avg_container[n] += len(i)

# diviving all sums by n
for i in range(len(avg_container)):
    avg_container[i] = avg_container[i]/n

# combine header and average array into one item to write to csv
avg_output = []
avg_output.extend((info[0],avg_container))
print(avg_output)  # just for you to see for yourself

# outputting the new file
output_csv = open(output_file, 'w', newline='')  # creates an instance of the file
csv_writer = csv.writer(output_csv)  # creates an "Writer" to write to the csv
csv_writer.writerows(avg_output)  # outputs the avg_output variable to the csv file
output_csv.close()  # finished

参考

How to import a csv-file into a data array?

Create a .csv file with values from a Python list

Writing a Python list of lists to a csv file

如何获取csv中每列中字符串的平均长度？

4 个答案: