Writing the iterative output into a file in python

问题

I am trying to write the output of my print statements into an output file instead of printing them at console. Is there any simple way to do that without affecting the code written in my print statements?

Code :-

outputfile = open('output1.txt','w')    
outputfile.write("Order_id  Order_date  User_id    Avg_Item_Price    Start_page_url     Error_msg")


for i in inputm[1:]:    
     if '::' in i[0] or ':' not in i[0]:        
         print('\n',"This is not a valid order record.") 
     else: 
         print('\n',i[0].split(':')[0]
                              ,str(datetime.strptime(i[0].split(':')[1],'%Y%m%d'))[:10]
                              ,i[1]
                              ,round(sum( float(v) if v else 0.0 for v in i[2:6])/4,2)
                              ,i[6] if Counter(i[6][0:23])  == Counter("http://www.google.com") else '                              '
                              ,'Valid URL' if Counter(i[6][0:23])  == Counter("http://www.google.com")  else 'Invalid URL'                
                          )

outputfile.close()  

回答1:

You need to format your string before writing to file!!

print('\n,',"This is not a valid order record.")

to

output file.write('\n %s'%("This is not a valid order record.")

that is

outputfile = open('output1.txt','w')    


outputfile.write("Order_id  Order_date  User_id    Avg_Item_Price    Start_page_url     Error_msg")


for i in inputm[1:]:    
     if '::' in i[0] or ':' not in i[0]:        
         outputfile.write('\n %s'%("This is not a valid order record."))
     else: 
         outputfile.write('\n%s %s %s %f %s %s'%(i[0].split(':')[0]
                              ,str(datetime.strptime(i[0].split(':')[1],'%Y%m%d'))[:10]
                              ,str(i[1])
                              ,round(sum( float(v) if v else 0.0 for v in i[2:6])/4,2)
                              ,i[6] if Counter(i[6][0:23])  == Counter("http://www.google.com") else '                              '
                              ,'Valid URL' if Counter(i[6][0:23])  == Counter("http://www.google.com")  else 'Invalid URL'))

outputfile.close()  

回答2:

If you don't want to change any of your code, you could change the print function to append to the file instead:

def print(*args):
    with open("output1.txt", "a") as outputfile:
        outputfile.write(" ".join(str(arg) for arg in args) + "\n")

But it would be better to create a new function like this:

def write_to_file(*args):
    with open("output1.txt", "a") as outputfile:
        outputfile.write(" ".join(str(arg) for arg in args) + "\n")

write_to_file("Order_id  Order_date  User_id    Avg_Item_Price    Start_page_url     Error_msg")

for i in inputm[1:]:    
     if '::' in i[0] or ':' not in i[0]:        
         write_to_file('\n',"This is not a valid order record.") 
     else: 
         write_to_file('\n',i[0].split(':')[0]
                              ,str(datetime.strptime(i[0].split(':')[1],'%Y%m%d'))[:10]
                              ,i[1]
                              ,round(sum( float(v) if v else 0.0 for v in i[2:6])/4,2)
                              ,i[6] if Counter(i[6][0:23])  == Counter("http://www.google.com") else '                              '
                              ,'Valid URL' if Counter(i[6][0:23])  == Counter("http://www.google.com")  else 'Invalid URL'                
                          )

outputfile.close()  

来源：https://stackoverflow.com/questions/43233717/writing-the-iterative-output-into-a-file-in-python