Question

过去几个小时一直试图解决这个问题，我找不到解决办法！基本上我们必须编写一个程序来打开一个文件，从中获取数字，并计算上述内容（平均值，最小值，最大值，标准派生值）。以下是我目前的情况：

def get_numbers():

 # Open a file for reading.
infile = open('inNumbers.txt', 'r')

# Read the numbers from the file.
line = infile.readline()
while line != '':
    print(line)
    line = infile.readline()
infile.close()


def mean(nums):
    sum = 0.0
    for num in nums:
        sum = sum + num
    return sum / len(nums)


def stdDev(nums, xbar):
    sumDevSq = 0.0
    for num in nums:
        dev = xbar - num
        sumDevSq = sumDevSq + dev * dev
    return sqrt(sumDevSq/(len(nums)-1))


def min():
    showFile = open("inNumbers.txt", 'r')
    lowest = None
    for line in showFile:
        tokens = line.split(',')
        value = min(tokens[:2])
        if lowest == None:
            lowest = value
        if value < lowest:
                lowest = value


def main():
    print("This program computes mean, maximum, minimum and standard deviation.")

    data = get_numbers()
    xbar = mean(data)
    std = stdDev(data, xbar)

    print("\nThe mean is", xbar)
    print("The standard deviation is", std)
    print("The minimum is", value)

main（）的

Answer 1

正如我所指出的那样，在尝试解决当前问题之前，你应该首先阅读一些关于编程的基本引子，否则任何答案都不会帮助你，而只会创造一个货币崇拜的新门徒。 / p>

然而，这里是你的代码（虽然我不确定std-dev的公式）：

#open file
with open('inNumbers.txt', 'r') as f:
    #read lines, strip trailing newlines, and convert to float if not empty
    numbers = [float(x) for x in (x.strip() for x in f) if x]

avg = sum(numbers) / len(numbers)
sdv = (sum((n - avg) ** 2 for n in numbers) / len(numbers)) ** .5
print('The arithmetic mean is {}'.format(avg))
print('The standard deviation is {}'.format(sdv))
print('The minimum is {}.'.format(min(numbers)))

也许你可以从中获取一些有用的东西。

Answer 2

了解包含数字的文件的外观非常重要。但我将从您的示例代码中假设每行有一个浮点数。如果你已经安装了numpy会更容易。我猜这是默认在Mac上。所以一步一步：

import numpy

#define a function that will just open your file containing numbers and get 
#all data into a list of floats
def getNumbers(file):
  numbers = []
  with open(file, 'r') as numbers_file:
    for line in numbers_file.readlines():
      numbers.append(float(line.strip('\n').strip()))
  return numbers


#get data from 'numbers.txt' into a list named 'num_list'
num_list = getNumbers('numbers.txt')

#print what you need
print 'Maximum is %g' %max(num_list)
print 'Minimum is %g' %min(num_list)
print 'Average is %g' %numpy.mean(num_list)
print 'Standard deviation is %g' %numpy.std(num_list)

#if you do not have numpy
my_avg = sum(num_list)/len(num_list)
print 'Average is %g' %my_avg
#you need to do some reading for the std-dev formula :)

编写一个计算平均值，中位数，最大值和标准差的程序

2 个答案: