使用换行符Python打印字符串

Question

import csv
import datetime
with open('soundTransit1_remote_rawMeasurements_15m.txt','r') as infile, open('soundTransit1.txt','w') as outfile:
    inr = csv.reader(infile,delimiter='\t')
    #ouw = csv.writer(outfile,delimiter=' ')
    for row in inr:
        d = datetime.datetime.strptime(row[0],'%Y-%m-%d %H:%M:%S')
        s = 1
        p = int(row[5])
        nr = [format(s,'02')+format(d.year,'04')+format(d.month,'02')+format(d.day,'02')+format(d.hour,'02')+format(d.minute,'02')+format(int(p*0.2),'04')]
        outfile.writelines(nr+'/n')

Using the above script, I have read in a .txt file and reformatted it as 'nr' so it looks like this:

['012015072314000000']
['012015072313450000']
['012015072313300000']
['012015072313150000']
['012015072313000000']
['012015072312450000']
['012015072312300000']
['012015072312150000']

..etc.

I need to now print it onto my new .txt file, but Python is not allowing me to print 'nr' with line breaks after each entry, I think because the data is in strings. I get this error:

TypeError: can only concatenate list (not "str") to list

Is there another way to do this?

Answer 1

You are trying to combine a list with a string, which cannot work. Simply don't create a list in nr .

import csv
import datetime
with open('soundTransit1_remote_rawMeasurements_15m.txt','r') as infile, open('soundTransit1.txt','w') as outfile:
    inr = csv.reader(infile,delimiter='\t')
    #ouw = csv.writer(outfile,delimiter=' ')
    for row in inr:
        d = datetime.datetime.strptime(row[0],'%Y-%m-%d %H:%M:%S')
        s = 1
        p = int(row[5])
        nr = "{:02d}{:%Y%m%d%H%M}{:04d}\n".format(s,d,int(p*0.2))
        outfile.write(nr)

Answer 2

There is no need to put your string into a list; just use outfile.write() here and build a string without a list:

nr = format(s,'02') + format(d.year,'04') + format(d.month, '02') + format(d.day, '02') + format(d.hour, '02') + format(d.minute, '02') + format(int(p*0.2), '04')
outfile.write(nr + '\n')

Rather than use 7 separate format() calls, use str.format() :

nr = '{:02}{:%Y%m%d%H%M}{:04}\n'.format(s, d, int(p * 0.2))
outfile.write(nr)

Note that I formatted the datetime object with one formatting operation, and I included the newline into the string format.

You appear to have hard-coded the s value; you may as well put that into the format directly:

nr = '01{:%Y%m%d%H%M}{:04}\n'.format(d, int(p * 0.2))
outfile.write(nr)

Together, that updates your script to:

with open('soundTransit1_remote_rawMeasurements_15m.txt', 'r') as infile,\
        open('soundTransit1.txt','w') as outfile:
    inr = csv.reader(infile, delimiter='\t')
    for row in inr:
        d = datetime.datetime.strptime(row[0], '%Y-%m-%d %H:%M:%S')
        p = int(int(row[5]) * 0.2)
        nr = '01{:%Y%m%d%H%M}{:04}\n'.format(d, p)
        outfile.write(nr)

Take into account that the csv module works better if you follow the guidelines about opening files; in Python 2 you need to open the file in binary mode ( 'rb' ), in Python 3 you need to set the newline parameter to '' . That way the module can control newlines correctly and supports including newlines in column values.