I have a very large string in the CSV format that will be written to a CSV file.
I try to write it to CSV using the simplest if the python script
results=""" "2013-12-03 23:59:52","/core/log","79.223.39.000","logging-4.0",iPad,Unknown,"1.0.1.59-266060",NA,NA,NA,NA,3,"1385593191.865",true,ERROR,"app_error","iPad/Unknown/webkit/537.51.1",NA,"Does+not",false
"2013-12-03 23:58:41","/core/log","217.7.59.000","logging-4.0",Win32,Unknown,"1.0.1.59-266060",NA,NA,NA,NA,4,"1385593120.68",true,ERROR,"app_error","Win32/Unknown/msie/9.0",NA,"Does+not,false
"2013-12-03 23:58:19","/core/client_log","79.240.195.000","logging-4.0",Win32,"5.1","1.0.1.59-266060",NA,NA,NA,NA,6,"1385593099.001",true,ERROR,"app_error","Win32/5.1/mozilla/25.0",NA,"Could+not:+{"url":"/all.json?status=ongoing,scheduled,conflict","code":0,"data":"","success":false,"error":true,"cached":false,"jqXhr":{"readyState":0,"responseText":"","status":0,"statusText":"error"}}",false"""
resultArray = results.split('\n')
with open(csvfile, 'wb') as f:
writer = csv.writer(f)
for row in resultArray:
writer.writerows(row)
The code returns
"Unknown Dialect"
Error
Is the error because of the script or is it due to the string that is being written?
EDIT
If the problem is bad input how do I sanitize it so that it can be used by the csv.writer() method?
You need to specify the format of your string:
with open(csvfile, 'wb') as f:
writer = csv.writer(f, delimiter=',', quotechar="'", quoting=csv.QUOTE_ALL)
You might also want to re-visit your writing loop; the way you have it written you will get one column in your file, and each row will be one character from the results string.
To really exploit the module, try this:
import csv
lines = ["'A','bunch+of','multiline','CSV,LIKE,STRING'"]
reader = csv.reader(lines, quotechar="'")
with open('out.csv', 'wb') as f:
writer = csv.writer(f)
writer.writerows(list(reader))
out.csv will have:
A,bunch+of,multiline,"CSV,LIKE,STRING"
If you want to quote all the column values, then add quoting=csv.QUOTE_ALL to the writer object; then you file will have:
"A","bunch+of","multiline","CSV,LIKE,STRING"
To change the quotes to ', add quotechar="'" to the writer object.
The above code does not give csv.writer.writerows input that it expects. Specifically:
resultArray = results.split('\n')
This creates a list of strings. Then, you pass each string to your writer and tell it to writerows with it:
for row in resultArray:
writer.writerows(row)
But writerows does not expect a single string. From the docs:
csvwriter.writerows(rows)
Write all the rows parameters (a list of row objects as described above) to the writer’s file object, formatted according to the current dialect.
So you're passing a string to a method that expects its argument to be a list of row objects, where a row object is itself expected to be a sequence of strings or numbers:
A row must be a sequence of strings or numbers for Writer objects
Are you sure your listed example code accurately reflects your attempt? While it certainly won't work, I would expect the exception produced to be different.
For a possible fix - if all you are trying to do is to write a big string to a file, you don't need the csv library at all. You can just write the string directly. Even splitting on newlines is unnecessary unless you need to do something like replacing Unix-style linefeeds with DOS-style linefeeds.
If you need to use the csv module after all, you need to give your writer something it understands - in this example, that would be something like writer.writerow(['A','bunch+of','multiline','CSV,LIKE,STRING']). Note that that's a true Python list of strings. If you need to turn your raw string "'A','bunch+of','multiline','CSV,LIKE,STRING'" into such a list, I think you'll find the csv library useful as a reader - no need to reinvent the wheel to handle the quoted commas in the substring 'CSV,LIKE,STRING'. And in that case you would need to care about your dialect.
you can use 'register_dialect':
for example for escaped formatting:
csv.register_dialect('escaped', escapechar='\\', doublequote=True, quoting=csv.QUOTE_ALL)
Related
I'm doing some measurements in the lab and want to transform them into some nice Python plots. The problem is the way the software exports CSV files, as I can't find a way to properly read the numbers. It looks like this:
-10;-0,0000026
-8;-0,00000139
-6;-0,000000546
-4;-0,000000112
-2;-5,11E-09
0,0000048;6,21E-09
2;0,000000318
4;0,00000304
6;0,0000129
8;0,0000724
10;0,000268
Separation by ; is fine, but I need every , to be ..
Ideally I would like Python to be able to read numbers such as 6.21E-09 as well, but I should be able to fix that in excel...
My main issue: Change every , to . so Python can read them as a float.
The simplest way would be for you to convert them to string and then use the .replace() method to pretty much do anything. For i.e.
txt = "0,0000048;6,21E-09"
txt = txt.replace(';', '.')
You could also read the CSV file (I don't know how you are reading the file) but depending on the library, you could change the 'delimiter' (to : for example). CSV is Comma-separated values and as the name implies, it separates columns by means of '.
You can do whatever you want in Python, for example:
import csv
with open('path_to_csv_file', 'r') as csv_file:
data = list(csv.reader(csv_file, delimiter=';'))
data = [(int(raw_row[0]), float(raw_row[1].replace(',', '.'))) for row in data]
with open('path_to_csv_file', 'w') as csv_file:
writer = csv.writer(csv_file, delimiter=';')
writer.writerows(data)
Can you consider a regex to match the ',' all in the text, then loop the match results in a process that takes ',' to '.'.
I was hoping someone could help me with this. I'm getting a file from a form in Django, this file is a csv and I'm trying to read it with Python's library csv. The problem here is that when I apply the function csv.reader and I turn that result into a list in order to print it, I find out that csv.reader is not splitting correctly my file.
Here are some images to show the problem
This is my csv file:
This my code:
And this is the printed value of the variable file_readed:
As you can see in the picture, it seems to be splitting my file character by character with some exceptions.
I thank you for any help you can provide me.
If you are pulling from a web form, try getting the csv as a string, confirm in a print or debug tool that the result is correct, and then pass it to csv using StringIO.
from io import StringIO
import csv
csv_string = form.files['carga_cie10'].file_read().decode(encoding="ISO-88590-1")
csv_file = StringIO(csv_string)
reader = csv.reader(csvfile, delimiter=',', quotechar='"')
for row in reader:
print(row)
Another thing you can try is changing the lineterminator argument to csv.reader(). It can default to \r\n but the web form might use some other value. Inspect the string you get from the web form to confirm.
that CSV does not seem right: you got some lines with more arguments than others.
The acronym of CSV being Comma Separated Values, you need to have the exact same arguments separated by commas for each line, or else it will mess it up.
I see in your lines you're maybe expecting to have 3 columns, instead you got lines with 2, or 4 arguments, and some of them have an opening " in one argument, comma, then closing " in the second argument
check if your script works with other CSVs maybe
Most likely you need to specify delimiter. Since you haven't explicitly told about the delimiter, I guess it's confused.
csv.reader(csvfile, delimiter=',')
However, since there are quotations with comma delimiter, you may need to alter the default delimiter on the CSV file's creation too for tab or something else.
The problem is here:
print(list(file_readed))
'list' is causing printing of every element within the csv as an individual unit.
Try this instead:
with open('carga_cie10') as f:
reader = csv.reader(f)
for row in reader:
print(" ".join(row))
Edit:
import pandas as pd
file_readed = pd.read_csv(file_csv)
print(file_readed)
The output should look clean. Pandas is highly useful in situations where data needs to be read, manipulated, changed, etc.
I am using a certain REST api to get data, and then attemping to write it to a csv using python 2.7
In the csv, every item with a tuple has u' ' around it. For example, with the 'tags' field i am retrieving, i am getting [u'01d/02d/major/--', u'45m/04h/12h/24h', u'internal', u'net', u'premium_custom', u'priority_fields_swapped', u'priority_saved', u'problem', u'urgent', u'urgent_priority_issue'] . However, if I print the data in the program prior to it being written in the csv, the data looks fine, .ie ('01d/02d/major--', '45m/04h/12h/24h', etc). So I am assuming I have to modify something in the csv write command or within the the csv writer object itself. My question is how to write the data into the csv properly so that there are no unicode characters.
In Python3:
Just define the encoding when opening the csv file to write in.
If the row contains non ascii chars, you will get UnicodeEncodeError
row = [u'01d/02d/major/--', u'45m/04h/12h/24h', u'internal', u'net', u'premium_custom', u'priority_fields_swapped', u'priority_saved', u'problem', u'urgent', u'urgent_priority_issue']
import csv
with open('output.csv', 'w', newline='', encoding='ascii') as f:
writer = csv.writer(f)
writer.writerow(row)
I have a python list as such:
[['a','b','c'],['d','e','f'],['g','h','i']]
I am trying to get it into a csv format so I can load it into excel:
a,b,c
d,e,f
g,h,i
Using this, I am trying to write the arary to a csv file:
with open('tables.csv','w') as f:
f.write(each_table)
However, it prints out this:
[
[
'
a
'
,
...
...
So then I tried putting it into an array (again) and then printing it.
each_table_array=[each_table]
with open('tables.csv','w') as f:
f.write(each_table_array)
Now when I open up the csv file, its a bunch of unknown characters, and when I load it into excel, I get a character for every cell.
Not too sure if it's me using the csv library wrong, or the array portion.
I just figured out that the table I am pulling data from has another table within one of its cells, this expands out and messes up the whole formatting
You need to use the csv library for your job:
import csv
each_table = [['a','b','c'],['d','e','f'],['g','h','i']]
with open('tables.csv', 'w') as csvfile:
writer = csv.writer(csvfile)
for row in each_table:
writer.writerow(row)
As a more flexible and pythonic way use csv module for dealing with csv files Note that as you are in python 2 you need the method newline='' * in your open function . then you can use csv.writer to open you csv file for write:
import csv
with open('file_name.csv', 'w',newline='') as csvfile:
spamwriter = csv.writer(csvfile, delimiter=',')
spamwriter.writerows(main_list)
From python wiki: If newline='' is not specified, newlines embedded inside quoted fields will not be interpreted correctly, and on platforms that use \r\n linendings on write an extra \r will be added. It should always be safe to specify newline='', since the csv module does its own (universal) newline handling.
I have a process where a CSV file can be downloaded, edited then uploaded again. On the download, the CSV file is in the correct format, with no wrapping double quotes
1, someval, someval2
When I open the CSV in a spreadsheet, edit and save, it adds double quotes around the strings
1, "someEditVal", "someval2"
I figured this was just the action of the spreadsheet (in this case, openoffice). I want my upload script to remove the wrapping double quotes. I cannot remove all quotes, just incase the body contains them, and I also dont want to just check first and last characters for double quotes.
Im almost sure that the CSV library in python would know how to handle this, but not sure how to use it...
EDIT
When I use the values within a dictionary, they turn out as follows
{'header':'"value"'}
Thanks
For you example, the following works:
import csv
writer = csv.writer(open("out.csv", "wb"), quoting=csv.QUOTE_NONE)
reader = csv.reader(open("in.csv", "rb"), skipinitialspace=True)
writer.writerows(reader)
You might need to play with the dialect options of the CSV reader and writer -- see the documentation of the csv module.
Thanks to everyone who was trying to help me, but I figured it out. When specifying the reader, you can define the quotechar
csv.reader(upload_file, delimiter=',', quotechar='"')
This handles the wrapping quotes of strings.
For Python 3:
import csv
writer = csv.writer(open("query_result.csv", "wt"), quoting=csv.QUOTE_NONE, escapechar='\\')
reader = csv.reader(open("out.txt", "rt"), skipinitialspace=True)
writer.writerows(reader)
The original answer gives this error under Python 3. Also See this SO for detail: csv.Error: iterator should return strings, not bytes
Traceback (most recent call last):
File "remove_quotes.py", line 11, in
writer.writerows(reader)
_csv.Error: iterator should return strings, not bytes (did you open the file in text mode?)