Question

这可能吗？我想一次在我的文件中打印行（以批量发送到API）。但是当我到达最后几行时，他们从不打印，因为少于5行，从不触发我的if语句打印。所以我认为解决这个问题的一种方法是在循环关闭时打印剩余的行。

目前的代码很乱并且多余，但这就是这个想法：

urls = []
urls_csv = ""
counter = 0

with open(urls_file) as f:
    for line in f:

        # Keep track of the lines we've went through
        counter = counter + 1

        # If we have 5 urls in our list it's time to send them to the API call
        if counter > 5:
            counter = 0
            urls_csv = ",".join(urls) # turn the python list into a string csv list
            do_api(urls_csv) # put them to work

            urls = [] # reset the value so we don't send the same urls next time
            urls_csv = "" # reset the value so we don't send the same urls next time
         # Else append to the url list
         else:
            urls.append(line.strip))

另外 - 一般来说，有没有更好的方法来解决这个问题？

Answer 1

您可以使用itertools grouper recipe将它们分组为5行。

import itertools

def grouper(iterable, n, fillvalue=None):
    args = [iter(iterable)] * n
    return itertools.zip_longest(*args, fillvalue=fillvalue)

with open(...) as f:
    for group in grouper(f, 5, fillvalue=""):
        do_api(",".join([g.strip() for g in group if g]))

Answer 2

您如何看待

urls = []

with open(urls_file) as f:
    while True:
        try:
            for i in range(5):
                urls.append(next(f).rstrip())
            print(urls)  # i.e. you have the list of urls, now use it/put it to work
            urls = []
        except StopIteration:
            print(urls)
            break

输入文件

line1
line2
line3
line4
line5
line6
line7

它产生

['line1', 'line2', 'line3', 'line4', 'line5']
['line6', 'line7']

如何在循环结束时触发某些东西？

2 个答案: