Develop Reference

Want to convert the csv file from line break mode to be separated by comma

Currently the csv file is saved in line break mode. But it should be separated by comma for inputting these datas as an array.
The current csv file:
test#eaxmple.com
test#eaxmple.com
test#eaxmple.com
The ideal csv file:
test#eaxmple.com, test#eaxmple.com, test#eaxmple.com
The code:
def get_addresses():
with open('./addresses.csv') as f:
addresses_file = csv.reader(f)
# Need to be converted
How can I convert it? I hope to use Python.
tried this.
with open('./addresses.txt') as input, open('./addresses.csv', 'w') as output:
output.write(','.join(input.readlines()))
output.write('\n')
the result:
test#eaxmple.com
,test#eaxmple.com
,test#eaxmple.com

with open('./addresses.txt') as f:
print(",".join(f.read().splitlines()))

Load the original file into pandas using:
import pandas as pd
df = pd.read_csv({YOUR_FILE}, escapechar='\\')
Then export it back to .csv (by default this will be comma separated).
df.to_csv({YOUR_FILE})

For this simple task, just read them into an array, then join the array on commas.
with open('./addresses.txt') as input, open('./addresses.csv', 'w') as output:
output.write(','.join(input.read().splitlines()))
output.write('\n')
This ignores any complications in the CSV formatting - if your data could contain commas (which are reserved as the field separator) or double quotes (which are reserved for quoting other reserved characters) you will want to switch to the proper csv module for output and perhaps for input.
Overwriting your input file is also an unnecessary complication, so I suggest you rename the input file to addresses.txt and use addresses.csv only for output.
Demo: https://repl.it/repls/AdequateStunningVideogames
Another common trick is to read one line at a time, and write a separator before each output except the first. This is more scalable for large input files.
with open blah blah blah ...:
separator = '' # for first line
for line in input:
output.write(separator)
output.write(line)
separator = ',' # for subsequent input lines
output.write('\n')

python csv to tsv: in case record has comma inside

I'm trying to convert csv format to tsv.
I just used this to change comma to tab.
tsv = re.sub(',', '\t', csv)
But I can't deal with the string with comma inside, for example:
dept_no,dt,hello
1,20180411,hello its me
2,20180412,here has tab
3,20180412,"here, is, commas"
Is there any way to convert to tsv without affecting comma inside of the string?

Try following, csv module should take care of inline commas.
import csv
csv.writer(file('output.tsv', 'w+'), delimiter='\t').writerows(csv.reader(open("input.csv")))
EDIT-1
[Added open method as per discussion]
Insted of using file where we are calling constructor directly, you can use open which is preferred way as per documentation here.
Result is same.
csv.writer(open('output.tsv', 'w+'), delimiter='\t').writerows(csv.reader(open("input.csv")))
Result

Keeping format of text (.txt) files when reading and rewriting

I have a .txt file containing formatting elements as \n for line breaks which I want to read and then rewrite its data until a specific line back to a new .txt file. My code looks like this:
with open (filename) as f:
content=f.readlines()
with open("lf.txt", "w") as file1:
file1.write(str(content))
file1.close
The output file lf.txt is produced correctly but it throws away the formatting of the input file. Is there a way to keep the formatting of file 1 when rewriting it to a new file?

You converted content to a string, while it's really a list of strings (lines).
Use join to convert the lines back to a string:
file1.write(''.join(content))
join is a string method, and it is activated in the example from an empty string object. The string calling this method is used as a separator for the strings joining process. In this situation we don't need any separator, just joining the strings.

How to write lines in a txt file, with data from a csv file

How can I tell Python to open a CSV file, and merge all columns per line, into new lines in a new TXT file?
To explain:
I'm trying to download a bunch of member profiles from a website, for a research project. To do this, I want to write a list of all the URLs in a TXT file.
The URLs are akin to this: website.com-name-country-title-id.html
I have written a script that takes all these bits of information for each member and saves them in columns (name/country/title/id), in a CSV file, like this:
mark japan rookie married
john sweden expert single
suzy germany rookie married
etc...
Now I want to open this CSV and write a TXT file with lines like these:
www.website.com/mark-japan-rookie-married.html
www.website.com/john-sweden-expert-single.html
www.website.com/suzy-germany-rookie-married.html
etc...
Here's the code I have so far. As you can probably tell I barely know what I'm doing so help will be greatly appreciated!!!
import csv
x = "http://website.com/"
y = ".html"
csvFile=csv.DictReader(open("NameCountryTitleId.csv")) #This file is stored on my computer
file = open("urls.txt", "wb")
for row in csvFile:
strArgument=str(row['name'])+"-"+str(row['country'])+"-"+str(row['title'])+"-"+str(row['id'])
try:
file.write(x + strArgument + y)
except:
print(strArgument)
file.close()
I don't get any error messages after running this, but the TXT file is completely empty.

Rather than using a DictReader, use a regular reader to make it easier to join the row:
import csv
url_format = "http://website.com/{}.html"
csv_file = 'NameCountryTitleId.csv'
urls_file = 'urls.txt'
with open(csv_file, 'rb') as infh, open(urls_file, 'w') as outfh:
reader = csv.reader(infh)
for row in reader:
url = url_format.format('-'.join(row))
outfh.write(url + '\n')
The with statement ensures the files are closed properly again when the code completes.
Further changes I made:
In Python 2, open a CSV files in binary mode, the csv module handles line endings itself, because correctly quoted column data can have embedded newlines in them.
Regular text files should be opened in text mode still though.
When writing lines to a file, do remember to add a newline character to delineate lines.
Using a string format (str.format()) is far more flexible than using string concatenations.
str.join() lets you join a sequence of strings together with a separator.

its actually quite simple, you are working with strings yet the file you are opening to write to is being opened in bytes mode, so every single time the write fails and it prints to the screen instead. try changing this line:
file = open("urls.txt", "wb")
to this:
file = open("urls.txt", "w")
EDIT:
i stand corrected, however i would like to point out that with an absence of newlines or some other form of separator, how do you intend to use the URLs later on? if you put newlines between each URL they would be easy to recover

Print elements of a list to a .csv file

I am reading in a csv file and dealing with each line as a list. At the end, I'd like to reprint to a .csv file, but the lines aren't necessarily even. I obviously cannot just go "print row", since this will print it as a list. How can I print it in .csv format?

Read manual, there's a CSV writer method (with example too). Don't print the data, store them and then write them into CSV file
http://docs.python.org/library/csv.html#csv.writer

Assuming that "row" contains a list of strings, you could try using
print ",".join(row)

Though it looks like your question was more towards writing to a csv file rather than printing it to standard output, here an example to do the latter using StringIO:
import StringIO
import csv
a_list_from_csv_file = [['for', 'bar'], [1, 2]]
out_fd = StringIO.StringIO()
writer = csv.writer(out_fd, delimiter='|')
for row in a_list_from_csv_file:
writer.writerow(row)
print out_fd.getvalue()
Like this you can use the different delimiters or escape characters as used by the csv you are reading.

What do you mean by "the lines aren't necessarily even"? Are you using a homebrew CSV parser or are you using the csv module?
If the former and there's nothing special you need to escape, you could try something like
print ",".join([ '"' + x.replace('"', '""') + '"' for x in row])
If you don't want ""s around each field, maybe make a function like escape_field() that checks if it needs to be wrapped in double quotes and/or escaped.