计数器在CSV读取纸条时不工作

Question

这是我第一个关于Stackoverflow/step-into-real编码的Python脚本/问题。你知道吗

我希望计算某些字符串在我遍历的行中出现的次数，然后打印出值。我没有设置分隔符，因此只有一列。本质上，我是说，如果列包含所说的字符串，那么添加到计数器。你知道吗

问题是，所有变量的输出都是0。有什么建议吗？你知道吗

这是密码（抱歉太长了）。你知道吗

# read the CSV file

import csv
with open('example.csv', 'r') as csvfile:

reader = csv.reader(csvfile)

# set up counter variables
googlebot = 0
googlebot_mobile = 0
apis_google = 0
adsense = 0
adsbot_mobile_web_android = 0
adsbot_mobile_web = 0
adsbot = 0
googlebot_images = 0
googlebot_news = 0
googlebot_video = 0
mobile_adsense = 0
mobile_apps_android = 0

# set up counter identifiers
googlebot_string = 'Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.96 Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)'
googlebot_mobile_string = 'Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.96 Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)'
apis_google_string = 'APIs-Google (+https://developers.google.com/webmasters/APIs-Google.html)'
adsense_string = 'Mediapartners-Google'
adsbot_mobile_web_android_string = 'Mozilla/5.0 (Linux; Android 5.0; SM-G920A) AppleWebKit (KHTML, like Gecko) Chrome Mobile Safari (compatible; AdsBot-Google-Mobile; +http://www.google.com/mobile/adsbot.html)'
adbot_mobile_web_string = 'Mozilla/5.0 (iPhone; CPU iPhone OS 9_1 like Mac OS X) AppleWebKit/601.1.46 (KHTML, like Gecko) Version/9.0 Mobile/13B143 Safari/601.1 (compatible; AdsBot-Google-Mobile; +http://www.google.com/mobile/adsbot.html)'
adsbot_string = 'AdsBot-Google (+http://www.google.com/adsbot.html)'
googlebot_images_string = 'Googlebot-Image/1.0'
googlebot_news_string = 'Googlebot-News'
googlebot_video_string = 'Googlebot-Video/1.0'
mobile_adsense_string = 'compatible; Mediapartners-Google/2.1; +http://www.google.com/bot.html'
mobile_apps_android_string = 'AdsBot-Google-Mobile-Apps'

# iterate and search for/add to counter
for row in reader:
    if googlebot_string in row:
        googlebot += 1

    elif googlebot_mobile_string in row:
        googlebot_mobile += 1

    elif apis_google_string in row:
        apis_google += 1

    elif adsense_string in row:
        adsense += 1

    elif adsbot_mobile_web_android_string in row:
        adsbot_mobile_web_android += 1

    elif adbot_mobile_web_string in row:
        adsbot_mobile_web += 1

    elif adsbot_string in row:
        adsbot += 1

    elif googlebot_images_string in row:
        googlebot_images += 1

    elif googlebot_news_string in row:
        googlebot_news += 1

    elif googlebot_video_string in row:
        googlebot_video += 1

    elif mobile_adsense_string in row:
        mobile_adsense += 1

    elif mobile_apps_android_string in row:
        mobile_apps_android += 1



# print counts
print "Googlebot (Desktop): ", googlebot
print "Googlebot (Mobile): ", googlebot_mobile
print "APIs Google: ", apis_google
print "AdSense: ", adsense
print "AdsBot Mobile Web Android: ", adsbot_mobile_web_android
print "AdsBot Mobile Web: ", adsbot_mobile_web
print "AdsBot: ", adsbot
print "Googlebot Images: ", googlebot_images
print "Googlebot News: ", googlebot_news
print "Googlebot Video: ", googlebot_video
print "Mobile AdSense: ", mobile_adsense
print "Mobile Apps Android: ", mobile_apps_android

Answer 1

I have not set up a delimiter so there is only one column

如果不指定分隔符，则使用默认分隔符，即逗号,。因此，列表row中仍然可能有多个列，因此也可能有多个元素。你知道吗

现在，googlebot_string中的字符串也包含逗号，因此，如果这个字符串出现在您的输入CSV中，它就不会作为单个元素出现在row中。因此googlebot_string in row总是false。其他一些*_string字符串也有同样的问题。你知道吗

您可以将文件作为文本文件打开（无需使用csv模块）并遍历行。你知道吗

一个肮脏的解决方案是将输入文件中不存在的字符指定为csv.reader的分隔符。你知道吗

Answer 2

您正在with上下文管理器外部读取文件。 您的代码应该是：

with open('example.csv', 'r') as csvfile:
    reader = csv.reader(csvfile)

否则，您将在读取文件之前打开和关闭文件。你知道吗

编辑：

正如@yann vernier所指出的，reader必须在with块中使用。也就是说，for循环应该全部缩进。你知道吗