发出读取csv文件 [英] Issue reading csv file

问题描述

我无法使用python阅读已保存的csv：

  import csv 
 
 
 with open（'blah.csv'，'rb'）as csvfile：
 data = csv.reader（csvfile）
 row_count = sum（数据中的行为1）
 print row_count 
 
 
r = 1 
数据中的行：
 print r 
  

$ b $我的问题是，虽然python似乎识别该文件，并认识到row_count = 9（并打印此），它不打印r在后面的循环中的每一行。

此代码在我的计算机上正常运行，但不在www.pythonanywhere.com上的云中

解决方案

这是因为在下面的行 - row_count = sum（数据中的行为1） - 您已经读过文件，并且已经到了结束。所以当你再次尝试做 -

 对于数据行：
 print r 
  

它不会工作，因为 data p>

您可以尝试的许多方法之一是重新打开该文件以从头开始读取。

示例 -

  import csv 
 with open（'blah.csv'，'rb'）as csvfile：
 data = csv.reader（csvfile）
 row_count = sum（数据中的行为1）
 print row_count 
 
 with open（'blah.csv'，'rb'） as csvfile：
 data = csv.reader（csvfile）
r = 1 
对于数据行：
 print r 
  

虽然您也可以同时计算行数并将行打印到一个循环中，如 -

  import csv 
 with open（'blah.csv'，'rb'）as csvfile：
 data = csv.reader（csvfile）
 row_count = 0 
数据行中的行
 row_count + = 1 
打印行
打印row_count 
  

b $ b

你可以做的另一件事是 -

  csvfile.seek（0）＃使文件指向开始。 
  

示例 -

  import csv 
 with open（'blah.csv'，'rb'）as csvfile：
 data = csv.reader（csvfile）
 row_count = sum在数据中）
 print row_count 
 csvfile.seek（0）
r = 1 
对于数据行：
 print r 
  

I am having trouble reading a saved csv with python:

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

My issue is that although python seems to recognise the file and recognise that row_count = 9 (and prints this) it doesn't print r for each row in the later loop.

This code runs correctly on my computer, but not in the cloud on www.pythonanywhere.com

解决方案

That is because in the following line - row_count = sum(1 for row in data) - you have already read through the file and it has reached its end. So when you again try to do -

for row in data:
    print r

It would not work, because data file is at the end.

One of the many things you can try is re-openning the file again to read it from start.

Example -

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

Though you can also make both counting of lines and printing the line into a single loop like -

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

Another thing you can do is -

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

Example -

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

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