Question

我正在处理从文件中读取数据的作业。我试图总结文件中的所有偶数，但我不能让它读取超过第一行的数字。这是我到目前为止的代码：

infile = open('data.txt', 'r')
even_sum = 0
line = infile.readline()

while int(line) % 2 == 0:
    even_sum += int(line)
    line = infile.readline()


infile.close()

print('Sum of even numbers: ' + str(even_sum))

Answer 1

假设每一行只包含一个数字而不是多个数字：

with open('data.txt') as infile:  # using `with open()` you do not need to do `infile.close()`, that is done for you.
    even_sum = 0
    for line in infile:  # Iterate over the lines
        num = int(line)  # Avoid calling int() multiple times if you can.
        if num  % 2 == 0:  # Its an even number.
            even_sum += num
    print('Sum of even numbers: ' + str(even_sum))

单行使用sum()只是为了咯咯笑：

print('Sum of even numbers: ' + str(sum([int(l) for l in open('data.txt') if int(l) % 2 == 0])))

Answer 2

你的while循环进入无限循环，你错过了迭代文件：这是解决方案：

def sum_even():
    with open('test1.txt') as input_file: 
    # Looping through the file line by line
        even_sum = 0
        for line in input_file:
            if int(line) % 2 == 0:
                print line
                even_sum += int(line)

        print('Sum of even numbers: ' + str(even_sum))

if __name__ == "__main__":
    sum_even()

从文件中读取数据（python 3）

2 个答案: