Question

所以我试图跳过.txt文件中的几行，然后使用csv reader创建一个CSV文件。需要跳过18行。这可以完成工作，但我很确定有一种简单的方法可以跳过18行而不是使用next（）18次。

import csv
import os

my_file_name = os.path.abspath('LensBank.txt')
cleaned_file = "LensBankClean.csv"
with open(my_file_name, 'r', newline='') as infile, open(cleaned_file, 'w',newline='') as outfile:
    writer = csv.writer(outfile)
    cr =  csv.reader(infile, delimiter=',')

    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    next(cr)
    writer.writerow(next(cr))

    for line in (r[:20] for r in cr):
     writer.writerow(line)

这对我有用，但我如何将代码清理为更简单的版本。谢谢！

Answer 1

使用range：

main.py

Answer 2

for i in range(18):
    next(cr)

使用for循环。或者您可以使用itertools.dropwhile

for line in (r[:20] for i, r in itertools.dropwhile(lambda x: x[1] < 18 , enumerate(cr))):

Answer 3

你在下面使用了for循环，这很奇怪，但是没有考虑到同样的问题。

您的代码很容易被这样的代码替换

for i in range(18):
    next(cr)
writer.writerow(next(cr))

这将调用next（cr）18次，然后调用writer.writerow

Answer 4

这个怎么样，

java.lang.ClassCastException: org.apache.geronimo.mail.handlers.HttpHandler cannot be cast to javax.activation.DataContentHandler jax rs

如@PatrickHaugh所述，上述解决方案对大文件无效。以下是大文件的解决方案。

import csv

# read a csv file into a list of lists
with open(in_file, 'r') as f_in:
    lists = [row for row in csv.reader(f_in, delimiter=',')] 

# write a list of lists to a csv file
with open(out_file, 'w') as f_out:
    writer = csv.writer(f_out)
    writer.writerows(lists[18:])    # skip the first 18 lines

在Python

4 个答案: