On Wednesday, February 5, 2014 7:34:57 PM UTC-5, MRAB wrote:
> On 2014-02-06 00:10, Zhen Zhang wrote:
>
> > Hi, every one.
>
> >
>
> > I am a second year EE student.
>
> > I just started learning python for my project.
>
> >
>
> > I intend to parse a csv file with a format like
>
> >
>
> > 3520005,"Toronto (Ont.)",C
> > ,F,2503281,2481494,F,F,0.9,1040597,979330,630.1763,3972.4,1
>
> > 2466023,"Montréal (Que.)",V
> > ,F,1620693,1583590,T,F,2.3,787060,743204,365.1303,4438.7,2
>
> > 5915022,"Vancouver (B.C.)",CY
> > ,F,578041,545671,F,F,5.9,273804,253212,114.7133,5039.0,8
>
> > 3519038,"Richmond Hill (Ont.)",T
> > ,F,162704,132030,F,F,23.2,53028,51000,100.8917,1612.7,28
>
> >
>
> > into a text file like the following
>
> >
>
> > Toronto 2503281
>
> > Montreal 1620693
>
> > Vancouver 578041
>
> >
>
> > I am extracting the 1st and 5th column and save it into a text file.
>
> >
>
> > This is what i have so far.
>
> >
>
> >
>
> > [code]
>
> >
>
> > import csv
>
> > file = open('raw.csv')
>
> > reader = csv.reader(file)
>
> >
>
> > f = open('NicelyDone.text','w')
>
> >
>
> > for line in reader:
>
> > f.write("%s %s"%line[1],%line[5])
>
> >
>
> > [/code]
>
> >
>
> > This is not working for me, I was able to extract the data from the csv
> > file as line[1],line[5]. (I am able to print it out)
>
> > But I dont know how to write it to a .text file in the format i wanted.
>
> >
>
> % is an operator. When used with a format string on its left, its
>
> arguments go on its right. In the general case, those arguments should
>
> be put in a tuple, although if there's only one argument and it's not a
>
> tuple, you can write just that argument:
>
>
>
> f.write("%s %s" % (line[1], line[5]))
>
>
>
> > Also, I have to process the first column eg, "Toronto (Ont.)" into
> > "Toronto".
>
> > I am familiar with the function find(), I assume that i could extract
> > Toronto out of Toronto(Ont.) using "(" as the stopping character,
>
> > but based on my research , I have no idea how to use it and ask it to
> > return me the string(Toronto).
>
> >
>
> Use find to tell you the index of the "(" (if there isn't one then
>
> it'll return -1) and then slice the string to get the part preceding it.
>
>
>
> Another way is to use the "partition" method.
>
>
>
> Also, have a look at the "strip"/"lstrip"/"rstrip" methods.
>
>
>
> > Here is my question:
>
> > 1:What is the data format for line[1], if it is string how come
> > f.write()does not work. if it is not string, how do i convert it to a
> > string?
>
> > 2:How do i extract the word Toronto out of Toronto(Ont) into a string form
> > using find() or other methods.
>
> >
>
> > My thinking is that I could add those 2 string together like c=a+' ' +b,
> > that would give me the format i wanted.
>
> > So i can use f.write() to write into a file ;)
>
> >
>
> > Sorry if my questions sounds too easy or stupid.
>
> >
>
> > Thanks ahead
>
> >
>
> > Zhen
>
> >
Thanks for the reply, especially the tuple parts,
I was not familiar with this data format,
but i guess i should :)
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