Question

我目前正在进行一项涵盖定义功能的练习，并且在将所有支持功能放入主要功能方面遇到了麻烦。

以下是代码原来的样子..

fn = input('Enter filename: ')
f = open(fn)
f.readline()  # Skip the first two lines
f.readline()
line = f.readline()  # Line containing site info
stuff = line.split(',')
print('\nSite: {}.\n(lat, long) = ({}, {})'.format(stuff[0], stuff[3], stuff[4]))

# Now process body of file, accumulating monthly rainfalls.

f.readline()
f.readline()
f.readline()
f.readline()
f.readline()
f.readline()

line = f.readline()
stuff = line.split(',')
rfs = 12 * [0]  # Rainfall totals for months
while len(stuff) > 1:
    date = stuff[1]
    m = int(date[4:6])   # Month
    rainfall = float(stuff[2])
    rfs[m - 1] += rainfall
    line = f.readline()
    stuff = line.split(',')

# Print results

months = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec']
print('\nMonth  Rainfall')
for i in range(12):
    print(' {} {:6.1f}'.format(months[i], rfs[i]))

print('\nTotal rainfall = {:.1f}'.format(sum(rfs)))
f.close()

打印出来..

Enter filename:
Site: Christchurch Aero.
(lat, long) = (-43.493, 172.537)

Month  Rainfall
 Jan   58.0
 Feb   35.4
 Mar   54.2
 Apr   50.8
 May   52.6
 Jun   41.0
 Jul   29.4
 Aug   62.6
 Sep   21.4
 Oct   90.8
 Nov   63.6
 Dec   60.8

Total rainfall = 620.6

我已经尝试将此代码拆分为单独的函数，但每当我运行代码时它就会冻结，我不确定底层问题是什么。这就是我的......

def main():
    '''Main function, opens the text file, reads and then prints the
    relevant info'''
    file_input = input('Enter filename: ')
    file = open(file_input)

    file.readline()
    file.readline()

    site_line = file.readline()  # Line containing site info
    site_info = site_line.split(',')
    print('\nSite: {}.\n(lat, long) = ({}, {})'.
          format(site_info[0], site_info[3], site_info[4]))

    rfs = rainfall_function(file)

    print_rainfall(rfs)

def rainfall_function(file):
    '''Read text file for the required data and process the information'''   
    file.readline()
    file.readline()
    file.readline()
    file.readline()
    file.readline()
    file.readline()  

    rain_line = file.readline()
    rain_info = rain_line.split(',')
    rfs = 12 * [0]  # Rainfall totals for months
    while len(rain_info) > 1:
        date = rain_info[1]
        month = int(date[4:6])   # Month
        rainfall = float(rain_info[2])
        rfs[month - 1] += rainfall
    return rfs


def print_rainfall(rfs):
    '''Months to print rainfall statistics for'''
    months = ['Jan', 'Feb', 'Mar', 'Apr', ' May', 'Jun', 
              'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    print('\nMonth  Rainfall')

    for i in range(12):
        print(' {} {:6.1f}'.format(months[i], rfs[i]))

    print('\nTotal rainfall = {:.1f}'.format(sum(rfs)))     

main()

我很感激帮助!!

Answer 1

我还没有尝试过运行你的代码，但你有一个明显的无限循环：

while len(rain_info) > 1:
        date = rain_info[1]
        month = int(date[4:6])   # Month
        rainfall = float(rain_info[2])
        rfs[month - 1] += rainfall

这将循环len(rain_info) > 1，但循环内的任何内容都不会改变rain_info的长度。因此，如果输入此循环，它将永远不会再次离开。

插入print()语句以查看代码正在执行的操作通常很有用。如果你在这个循环之前和之后有一个打印，你会看到之前的打印，而不是看到后。如果你在循环中有一个打印，你会看到它重复。

单步执行代码也很有用。有几个可用于Python的调试器;我使用的那个是Wingware IDE中的那个。学生有一个免费版本。

编辑：看看你的原始代码，我明白为什么它没有无限循环。它包括以下几行：

while len(stuff) > 1:
    # ...lines omitted...
    line = f.readline()
    stuff = line.split(',')

因此，每次循环运行时，它会尝试读取另一个输入行，然后拆分它获得的行。由于原始while循环依赖于len(stuff)，因此循环可以因循环内的代码而终止。

将支持功能放入主要功能

1 个答案: