数据文件中的行均值

debugcn 发表于 Dev

尼克·查尔顿

我需要创建一个函数来计算数据文件（.csv）中每行数字的均值，然后将均值作为列表返回。

我设法获得了加在一起的数字的值，但是我不知道如何除以每行数据的长度，然后将结果输入要返回的列表中。

def line_averages(filename):
    """ compute the average value for every line, and return the average
    values in a list in the file "filename" """
    infile = open(filename, "r")
    all_input = infile.read()
    infile.close()
    lines = all_input.split('\n')       # remove lines
    for one_line in lines:
        values = one_line.split(',')    # remove commas
        line_sum = 0 
        print(values)
        for j in values:
            line_sum = line_sum + float(j)

更新：

这是我根据以下建议之一获得的新代码：

def line_averages(filename):
""" compute the average value for every line, and return the average
values in a list in the file "filename" """
f = open(filename, "r")
x = f.read()
f.close()
no_lines = x.split('\n')       # remove lines
means = []
for i in no_lines:
    no_commas = i.split(',')    # remove commas
    average = sum(no_commas) / len(no_commas)
    means.append(average)
return means

我收到此错误：

In [22]: line_averages("data.csv")
Traceback (most recent call last):

File "<ipython-input-29-e2e3fddb5de5>", line 1, in <module>
line_averages("data.csv")

File "E:/Google Drive/python_files/training4.py", line 19, in line_averages
average = sum(no_commas) / len(no_commas)

TypeError: unsupported operand type(s) for +: 'int' and 'str'

不知道出了什么问题？！

修剪

return_list = []
...
    average = sum(values) / len(values)
    return_list.append(average)

另外，请使用描述性变量名。单字母变量可以用于一次性索引，但不适用于任何具有持久含义的变量。

扰流板警报

# If you have the statistics package, use "mean" from that, instead.
def mean(coll):
    return float(sum(coll)) / max(len(coll), 1)

def line_averages(filename):
    """ compute the average value for every line, and return the average
    values in a list in the file "filename" """

    return [mean([int(values) for values in line.split(',')]) for line in open(filename)]

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