Question

我在使用python读取已保存的csv时遇到问题：

import csv


with open('blah.csv','rb') as csvfile:
    data = csv.reader( csvfile )
    row_count = sum(1 for row in data)
    print row_count


    r = 1
    for row in data:
        print r

我的问题是虽然python似乎识别文件并识别出row_count = 9（并打印出来），但它并没有为后面循环中的每一行打印r。

此代码可在我的计算机上正常运行，但不能在www.pythonanywhere.com上的云中运行

Answer 1

这是因为在以下行 - row_count = sum(1 for row in data)中 - 您已经读完了该文件并且已经到了结尾。所以，当你再次尝试做 -

for row in data:
    print r

它不起作用，因为data文件在最后。

您可以尝试的许多事情之一是再次重新打开文件以从头开始阅读。

示例 -

import csv
with open('blah.csv','rb') as csvfile:
    data = csv.reader( csvfile )
    row_count = sum(1 for row in data)
    print row_count

with open('blah.csv','rb') as csvfile:
    data = csv.reader( csvfile )
    r = 1
    for row in data:
        print r

虽然您也可以对行进行计数并将行打印成单个循环，如 -

import csv
with open('blah.csv','rb') as csvfile:
    data = csv.reader( csvfile )
    row_count = 0
    for row in data
        row_count += 1
        print row
    print row_count

你可以做的另一件事是 -

csvfile.seek(0) #to make the file point to the start.

示例 -

import csv
with open('blah.csv','rb') as csvfile:
    data = csv.reader( csvfile )
    row_count = sum(1 for row in data)
    print row_count
    csvfile.seek(0)
    r = 1
    for row in data:
        print r

问题阅读csv文件

1 个答案: