用python在新行上将文本写入txt文件？

Question

So I am trying to check whether a url exists and if it does I would like to write the url to a file using python. I would also like each url to be on its own line within the file. Here is the code I already have:

import urllib2  

CREATE A BLANK TXT FILE THE DESKTOP

urlhere = "http://www.google.com"   
print "for url: " + urlhere + ":"  

try: 
    fileHandle = urllib2.urlopen(urlhere)
    data = fileHandle.read()
    fileHandle.close()
    print "It exists"

Then, If the URL does exist, write the url on a new line in the text file

except urllib2.URLError, e:
    print 'PAGE 404: It Doesnt Exist', e

If the URL doesn't exist, don't write anything to the file.

---

Answer 1

How about something like this:

import urllib2

url  = 'http://www.google.com'
data = ''

try:
    data = urllib2.urlopen(url).read()
except urllib2.URLError, e:
    data = 'PAGE 404: It Doesnt Exist ' + e

with open('outfile.txt', 'w') as out_file:
   out_file.write(data)

Answer 2

The way you worded your question is a bit confusing but if I understand you correctly all your trying to do is test if a url is valid using urllib2 and if it is write the url to a file? If that is correct the following should work.

import urllib2
f = open("url_file.txt","a+")
urlhere = "http://www.google.com"   
print "for url: " + urlhere + ":"  

try: 
    fileHandle = urllib2.urlopen(urlhere)
    data = fileHandle.read()
    fileHandle.close()
    f.write(urlhere + "\n")
    f.close()
    print "It exists"

except urllib2.URLError, e:
    print 'PAGE 404: It Doesnt Exist', e

If you want to test multiple urls but don't want to edit the the python script you could use the following script by typing python python_script.py "http://url_here.com" . This is made possible by using the sys module where sys.argv[1] is equal to the first argument passed to python_script.py. Which in this example is the url (' http://url_here.com ').

import urllib2,sys
f = open("url_file.txt","a+")
urlhere = sys.argv[1]   
print "for url: " + urlhere + ":"  

try: 
    fileHandle = urllib2.urlopen(urlhere)
    data = fileHandle.read()
    fileHandle.close()
    f.write(urlhere+ "\n")
    f.close()
    print "It exists"

except urllib2.URLError, e:
    print 'PAGE 404: It Doesnt Exist', e

Or if you really wanted to make your job easy you could use the following script by typing the following into the command line python python_script http://url1.com,http://url2.com where all the urls you wish to test are separated by commas with no spaces.

import urllib2,sys
f = open("url_file.txt","a+")
urlhere_list = sys.argv[1].split(",")   

for urls in urlhere_list:
    print "for url: " + urls + ":" 
    try: 
        fileHandle = urllib2.urlopen(urls)
        data = fileHandle.read()
        fileHandle.close()
        f.write(urls+ "\n")

        print "It exists"

    except urllib2.URLError, e:
        print 'PAGE 404: It Doesnt Exist', e
    except:
        print "invalid url"
f.close()

sys.argv[1].split() can also be replaced by a python list within the script if you don't want to use the command line functionality. Hope this is of some use to you and good luck with your program.

note The scripts using command line inputs were tested on the ubuntu linux, so if you are using windows or another operating system I can't guarantee that it will work with the instructions given but it should.

Answer 3

Use requests :

import requests

def url_checker(urls):
    with open('somefile.txt', 'a') as f:
       for url in urls:
           r = requests.get(url)
           if r.status_code == 200:
              f.write('{0}\n'.format(url))

url_checker(['http://www.google.com','http://example.com'])