how to join various bits of string and data together using python

Question

Python newbie here. I've been working my way through this code to basically create a string which includes a date. I have bits of the code working to get the data I want, however I need help formatting to string to tie in the data together.

This is what I have so far:

def get_rectype_count(filename, rectype):
    return int(subprocess.check_output('''zcat %s |  '''
                                       '''awk 'BEGIN {FS=";"};{print $6}' | '''
                                       '''grep -i %r | wc -l''' %
                                       (filename, rectype), shell=True))

str = "MY VALUES ("
rectypes = 'click', 'bounce'
for myfilename in glob.iglob('*.gz'):
        #print (rectypes)
        print str.join(rectypes)
        print (timestr)
        print([get_rectype_count(myfilename, rectype)
                               for rectype in rectypes])

My output looks like this:

clickMY VALUES (bounce
'2015-07-01'
[222, 0]

I'm trying to create this output file:

MY VALUES ('2015-07-01', click, 222)
MY VALUES ('2015-07-01', bounce, 0)

Why not just tie together the pieces of the string with the string concatination operator? I.e. a+b . Also, if the print statement contains a trailing comma, it will not output a newline character. — Dov Grobgeld
– Dov Grobgeld, Commented Jul 2, 2015 at 5:08
str is a built-in type, you shouldn't redefine it. Very confusing! — Open AI - Opting Out
– Open AI - Opting Out, Commented Jul 2, 2015 at 5:10

Open AI - Opting Out · Accepted Answer · 2015-07-03 05:44:52Z

5

When you call join on a string it joins together everything in the sequence passed to it, using itself as the separator.

>>> '123'.join(['click', 'bounce'])
click123bounce

Python supports formatting strings using replacement fields:

>>> values = "MY VALUES ('{date}', {rec}, {rec_count})"
>>> values.format(date='2015-07-01', rec='click', rec_count=222)
"MY VALUES ('2015-07-01', click, 222)"

With your code:

for myfilename in glob.iglob('*.gz'):
    for rec in rectypes:
        rec_count = get_rectype_count(myfilename, rec)
        print values.format(date=timestr, rec=rec, rec_count=rec_count)

edit:

If you want to use join, you can join a newline, \n:

>>> print '\n'.join(['line1', 'line2'])
line1
line2

Putting it together:

print '\n'.join(values.format(date=timestr,
                              rec=rec,
                              rec_count=get_rectype_count(filename, rec))
                for filename in glob.iglob('*.gz')
                for rec in rectypes)

edited Jul 3, 2015 at 5:44

answered Jul 2, 2015 at 5:20

Open AI - Opting Out

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3 Comments

noober Over a year ago

Thanks for making it look easy.

noober Over a year ago

I was testing the other solution using join. Got the following syntax error: for filename in glob.iglob('*.gz') ^ SyntaxError: invalid syntax

Open AI - Opting Out Over a year ago

@noober there was a missing closing parenthesis for .format(

amit_183 · Accepted Answer · 2015-07-02 05:27:12Z

2

try this:

str1 = "MY VALUES ("
rectypes = ['click', 'bounce']
K=[]
for myfilename in glob.iglob('*.gz'):
        #print (rectypes)
        #print str.join(rectypes)

        #print (timestr)
        k=([get_rectype_count(myfilename, rectype)
                               for rectype in rectypes])

 for i in range(0,len(rectypes)):
      print str1+str(timestr)+","+rectypes[i]+","+str(k[i])+")"

edited Jul 2, 2015 at 5:27

answered Jul 2, 2015 at 5:19

amit_183

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