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Converting a Text .txt document to CSV .csv Using a Delimiter

I'd like to create a CSV from a TXT file. I have a text file with lines (300 lines+) separated by backslashes. I'd like each line to be a separate row, and each backslash to be a separate new column.
The text file looks like:
example 1\example 2\example 3\example 4
test 1\test 2\test 3\test 4
I'd like the CSV to look like:
Example 1
Example 2
Example 3
Example 4
Test 1
Test 2
Test 3
Test 4
So far I have:
import csv
with open('Report.txt') as report:
report_txt = report.read()
with open('Report.csv','w',newline='') as csvfile:
writer = csv.writer(csvfile)
writer.writerow(report_txt)
I know I need to use \ as a delimiter, but I'm not sure how. Thanks for any help!

Define your delimiter like this (escape the \):
reader = csv.reader(open("Report.csv"), delimiter="\\")
Code:
import csv
with open('Report.txt') as report:
reader = csv.reader(report, delimiter="\\")
with open('Report_output.csv', 'w', newline='') as csvfile:
writer = csv.writer(csvfile)
for line in reader:
writer.writerow(line)

First you got to split the string based on the delimeter. You can achieve this by using the split operator or regex.
import csv
with open('file.txt', 'r') as in_file:
stripped = (line.strip() for line in in_file)
lines = (line.split("\\") for line in stripped if line)
Then pretty much write it to the csv.
with open('report.csv', 'w') as out_file:
writer = csv.writer(out_file)
writer.writerows(lines)
Tweak your code accordingly. The concept is pretty much the same. Note the double backslash is to account for the escape character.

If you are just trying to convert that text into CSV, you can just replace every "\" character with ";" and you'll have a valid CSV file.
Else, if you want to do something with the parsed data before reexporting to CSV, you can read the file line by line and use the split() Method with "\", then rejoin and write line by line, like here:
with open('in.txt') as input_file:
with open('out.csv','a') as output_file:
txt_line = input_file.readline()
while txt_line:
cells = txt_line.split("\\")
# Do something with each cell...
csv_line = ";".join(cells)
output_file.write(csv_line)
txt_line = input_file.readline()

Parsing csv file into Boolean expression in Python

I've got a csv file such as:
cutsets
x1
x3,x5
x2
x4,x6
x5,x7
x6,x8
x7,x9
x6,x8,x10
I run the following Py script:
import csv
# Reads Boolean expression from cutsets file
expr = []
with open("MCS_overlap.csv", "r") as csv_file:
csv_reader = csv.reader(csv_file)
# skip the first row
next(csv_reader)
for lines in csv_reader:
expr = expr + lines + ['|']
del expr[-1]
final_expr=str(''.join(expr)).replace(",","&")
print("The Boolean expression is")
print(final_expr)
and get the output:
The Boolean expression is
x1|x3x5|x2|x4x6|x5x7|x6x8|x7x9|x6x8x10
With final_expr=str(''.join(expr)).replace(",","&") I was hoping to get a "&" between any two variables enclosed by a "|", e.g. "x4&x6","x6&x8&x10". But as can be seen the variables were simply concatenated. How do I accomplish insert "&" given I cannot change the format of the input file?
Thanks
Gui

Here you go:
expr =[]
f = open('MCS_overlap.csv')
expr.append(f.read())
final_expr = expr[0].replace('\n', '|').replace(',', '&')
print(final_expr)
Prints:
'x1|x3&x5|x2|x4&x6|x5&x7|x6&x8|x7&x9|x6&x8&x10'

Because you are using csv module, lines is a list and as a result expr is a list with elements being all x-es and some pipes |. You can print to see for yourself. When you do ''.join(expr) it just concatenates all elements, no commas (i.e. nothing to replace).
this should do
import csv
# Reads Boolean expression from cutsets file
with open("MCS_overlap.csv", "r") as csv_file:
csv_reader = csv.reader(csv_file)
# skip the first row
next(csv_reader)
lines = ('&'.join(line) for line in csv_reader)
final_expr = '|'.join(lines)
print(final_expr)
of course, you can do without csv module
with open("MCS_overlap.csv", "r") as csv_file:
next(csv_file)
lines = (line.strip().replace(',', "&") for line in csv_file)
final_expr = '|'.join(lines)
print(final_expr)
Note, both snippets not tested, but I expect to do the task for you.

Python: replace a string in a CSV file

I am a beginner and I have an issue with a short code. I want to replace a string from a csv to with another string, and put out a new
csv with an new name. The strings are separated with commas.
My code is a catastrophe:
import csv
f = open('C:\\User\\Desktop\\Replace_Test\\Testreplace.csv')
csv_f = csv.reader(f)
g = open('C:\\Users\\Desktop\\Replace_Test\\Testreplace.csv')
csv_g = csv.writer(g)
findlist = ['The String, that should replaced']
replacelist = ['The string that should replace the old striong']
#the function ?:
def findReplace(find,replace):
s = f.read()
for item, replacement in zip(findlist,replacelist):
s = s.replace(item,replacement)
g.write(s)
for row in csv_f:
print(row)
f.close()
g.close()

You can do this with the regex package re. Also, if you use with you don't have to remember to close your files, which helps me.
EDIT: Keep in mind that this matches the exact string, meaning it's also case-sensitive. If you don't want that then you probably need to use an actual regex to find the strings that need replacing. You would do this by replacing find_str in the re.sub() call with r'your_regex_here'.
import re
# open your csv and read as a text string
with open(my_csv_path, 'r') as f:
my_csv_text = f.read()
find_str = 'The String, that should replaced'
replace_str = 'The string that should replace the old striong'
# substitute
new_csv_str = re.sub(find_str, replace_str, my_csv_text)
# open new file and save
new_csv_path = './my_new_csv.csv' # or whatever path and name you want
with open(new_csv_path, 'w') as f:
f.write(new_csv_str)

How do I convert a table in notepad into CSV format?

I have this table of data in Notepad
But it's not really a table because there aren't like official columns. It's just looks like a table, but the data is organized using spaces.
I want to convert it into a CSV format. How should I go about doing this?
The panda python packages I am using for data analysis work best with CSV, as far as I understand.

Here is a hackjob python script to do exactly what you need. Just save the script as a python file and run it with the path of your input file as the only argument.
UPDATED: After reading the comments to my answer, my script now uses regular expressions to account for any number of spaces.
import re
from sys import argv
output = ''
with open(argv[1]) as f:
for i, line in enumerate(f.readlines()):
if i == 0:
line = line.strip()
line = re.sub('\s+', ',', line) + '\n'
else:
line = re.sub('\s\s+', ',', line)
output += line
with open(argv[1] + '.csv', 'w') as f:
f.write(output)

So this is put into a file (if you call it csvify.py) and executed as:
python csvify.py <input_file_name>
csvify.py:
from sys import argv
from re import finditer
#Method that returns fields separated by commas
def comma_delimit(line, ranges):
return ','.join(get_field(line, ranges))
#Method that returns field info in appropriate format
def get_field(line, ranges):
for span in ranges: #Iterate through column ranges
field = line[slice(*span)].strip() #Get field data based on range slice and trim
#Use str() function if field doesn't contain commas, otherwise use repr()
yield (repr if ',' in field else str)(field)
#Open the input text file from command line (readonly, closed automatically)
with open(argv[1], 'r') as inp:
#Convert the first line (assumed header) into range indexes
#Use finditer to split the line by word border until the next word
#This assumes no spaces within header names
columns = map(lambda match: match.span(), finditer(r'\b\w+\s*', inp.readline()))
inp.seek(0) #Reset file pointer to beginning to include header line
#Create new CSV based on input file name
with open(argv[1] + '.csv', 'w') as txt:
#Writes to file and join all converted lines with newline
txt.write('\n'.join(comma_delimit(line, columns) for line in inp.readlines()))

Replace multiple cell in csv python module

I've a large csv file(comma delimited). I would like to replace/rename few random cell with the value "NIL" to an empty string "".
I tried this to find the keyword "NIL" and replace with '' empty
string. But it's giving me an empty csv file
ifile = open('outfile', 'rb')
reader = csv.reader(ifile,delimiter='\t')
ofile = open('pp', 'wb')
writer = csv.writer(ofile, delimiter='\t')
findlist = ['NIL']
replacelist = [' ']
s = ifile.read()
for item, replacement in zip(findlist, replacelist):
s = s.replace(item, replacement)
ofile.write(s)

From seeing you code i fell you directly should
read the file
with open("test.csv") as opened_file:
data = opened_file.read()
then use regex to change all NIL to "" or " " and save back the data to the file.
import re
data = re.sub("NIL"," ",data) # this code will replace NIL with " " in the data string
NOTE: you can give any regex instead of NIL
for more info see re module.
EDIT 1: re.sub returns a new string so you need to return it to data.

A few tweaks and your example works. I edited your question to get rid of some indenting errors - assuming those were a cut/paste problem. The next problem is that you don't import csv ... but even though you create a reader and writer, you don't actually use them, so it could just be removed. So, opening in text instead of binary mode, we have
ifile = open('outfile') # 'outfile' is the input file...
ofile = open('pp', 'w')
findlist = ['NIL']
replacelist = [' ']
s = ifile.read()
for item, replacement in zip(findlist, replacelist):
s = s.replace(item, replacement)
ofile.write(s)
We could add 'with' clauses and use a dict to make replacements more clear
replace_this = { 'NIL': ' '}
with open('outfile') as ifile, open('pp', 'w') as ofile:
s = ifile.read()
for item, replacement in replace_this.items:
s = s.replace(item, replacement)
ofile.write(s)
The only real problem now is that it also changes things like "NILIST" to "IST". If this is a csv with all numbers except for "NIL", that's not a problem. But you could also use the csv module to only change cells that are exactly "NIL".
with open('outfile') as ifile, open('pp', 'w') as ofile:
reader = csv.reader(ifile)
writer = csv.writer(ofile)
for row in reader:
# row is a list of columns. The following builds a new list
# while checking and changing any column that is 'NIL'.
writer.writerow([c if c.strip() != 'NIL' else ' '
for c in row])