import csv
with open('thefile.csv', 'rb') as f:
data = list(csv.reader(f))
import collections
counter = collections.defaultdict(int)
for row in data:
counter[row[10]] += 1
with open('/pythonwork/thefile_subset11.csv', 'w') as outfile:
writer = csv.writer(outfile)
for row in data:
if counter[row[10]] >= 504:
writer.writerow(row)
This code reads thefile.csv, makes changes, and writes results to thefile_subset1.
However, when I open the resulting csv in Microsoft Excel, there is an extra blank line after each record!
Is there a way to make it not put an extra blank line?
The csv.writer module directly controls line endings and writes \r\n into the file directly. In Python 3 the file must be opened in untranslated text mode with the parameters 'w', newline='' (empty string) or it will write \r\r\n on Windows, where the default text mode will translate each \n into \r\n.
#!python3
with open('/pythonwork/thefile_subset11.csv', 'w', newline='') as outfile:
writer = csv.writer(outfile)
In Python 2, use binary mode to open outfile with mode 'wb' instead of 'w' to prevent Windows newline translation. Python 2 also has problems with Unicode and requires other workarounds to write non-ASCII text. See the Python 2 link below and the UnicodeReader and UnicodeWriter examples at the end of the page if you have to deal with writing Unicode strings to CSVs on Python 2, or look into the 3rd party unicodecsv module:
#!python2
with open('/pythonwork/thefile_subset11.csv', 'wb') as outfile:
writer = csv.writer(outfile)
Documentation Links
https://docs.python.org/3/library/csv.html#csv.writer
https://docs.python.org/2/library/csv.html#csv.writer
Opening the file in binary mode "wb" will not work in Python 3+. Or rather, you'd have to convert your data to binary before writing it. That's just a hassle.
Instead, you should keep it in text mode, but override the newline as empty. Like so:
with open('/pythonwork/thefile_subset11.csv', 'w', newline='') as outfile:
Note: It seems this is not the preferred solution because of how the extra line was being added on a Windows system. As stated in the python document:
If csvfile is a file object, it must be opened with the ‘b’ flag on platforms where that makes a difference.
Windows is one such platform where that makes a difference. While changing the line terminator as I described below may have fixed the problem, the problem could be avoided altogether by opening the file in binary mode. One might say this solution is more "elegent". "Fiddling" with the line terminator would have likely resulted in unportable code between systems in this case, where opening a file in binary mode on a unix system results in no effect. ie. it results in cross system compatible code.
From Python Docs:
On Windows, 'b' appended to the mode
opens the file in binary mode, so
there are also modes like 'rb', 'wb',
and 'r+b'. Python on Windows makes a
distinction between text and binary
files; the end-of-line characters in
text files are automatically altered
slightly when data is read or written.
This behind-the-scenes modification to
file data is fine for ASCII text
files, but it’ll corrupt binary data
like that in JPEG or EXE files. Be
very careful to use binary mode when
reading and writing such files. On
Unix, it doesn’t hurt to append a 'b'
to the mode, so you can use it
platform-independently for all binary
files.
Original:
As part of optional paramaters for the csv.writer if you are getting extra blank lines you may have to change the lineterminator (info here). Example below adapated from the python page csv docs. Change it from '\n' to whatever it should be. As this is just a stab in the dark at the problem this may or may not work, but it's my best guess.
>>> import csv
>>> spamWriter = csv.writer(open('eggs.csv', 'w'), lineterminator='\n')
>>> spamWriter.writerow(['Spam'] * 5 + ['Baked Beans'])
>>> spamWriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])
The simple answer is that csv files should always be opened in binary mode whether for input or output, as otherwise on Windows there are problems with the line ending. Specifically on output the csv module will write \r\n (the standard CSV row terminator) and then (in text mode) the runtime will replace the \n by \r\n (the Windows standard line terminator) giving a result of \r\r\n.
Fiddling with the lineterminator is NOT the solution.
A lot of the other answers have become out of date in the ten years since the original question. For Python3, the answer is right in the documentation:
If csvfile is a file object, it should be opened with newline=''
The footnote explains in more detail:
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.
Use the method defined below to write data to the CSV file.
open('outputFile.csv', 'a',newline='')
Just add an additional newline='' parameter inside the open method :
def writePhoneSpecsToCSV():
rowData=["field1", "field2"]
with open('outputFile.csv', 'a',newline='') as csv_file:
writer = csv.writer(csv_file)
writer.writerow(rowData)
This will write CSV rows without creating additional rows!
I'm writing this answer w.r.t. to python 3, as I've initially got the same problem.
I was supposed to get data from arduino using PySerial, and write them in a .csv file. Each reading in my case ended with '\r\n', so newline was always separating each line.
In my case, newline='' option didn't work. Because it showed some error like :
with open('op.csv', 'a',newline=' ') as csv_file:
ValueError: illegal newline value: ''
So it seemed that they don't accept omission of newline here.
Seeing one of the answers here only, I mentioned line terminator in the writer object, like,
writer = csv.writer(csv_file, delimiter=' ',lineterminator='\r')
and that worked for me for skipping the extra newlines.
with open(destPath+'\\'+csvXML, 'a+') as csvFile:
writer = csv.writer(csvFile, delimiter=';', lineterminator='\r')
writer.writerows(xmlList)
The "lineterminator='\r'" permit to pass to next row, without empty row between two.
Borrowing from this answer, it seems like the cleanest solution is to use io.TextIOWrapper. I managed to solve this problem for myself as follows:
from io import TextIOWrapper
...
with open(filename, 'wb') as csvfile, TextIOWrapper(csvfile, encoding='utf-8', newline='') as wrapper:
csvwriter = csv.writer(wrapper)
for data_row in data:
csvwriter.writerow(data_row)
The above answer is not compatible with Python 2. To have compatibility, I suppose one would simply need to wrap all the writing logic in an if block:
if sys.version_info < (3,):
# Python 2 way of handling CSVs
else:
# The above logic
I used writerow
def write_csv(writer, var1, var2, var3, var4):
"""
write four variables into a csv file
"""
writer.writerow([var1, var2, var3, var4])
numbers=set([1,2,3,4,5,6,7,2,4,6,8,10,12,14,16])
rules = list(permutations(numbers, 4))
#print(rules)
selection=[]
with open("count.csv", 'w',newline='') as csvfile:
writer = csv.writer(csvfile)
for rule in rules:
number1,number2,number3,number4=rule
if ((number1+number2+number3+number4)%5==0):
#print(rule)
selection.append(rule)
write_csv(writer,number1,number2,number3,number4)
When using Python 3 the empty lines can be avoid by using the codecs module. As stated in the documentation, files are opened in binary mode so no change of the newline kwarg is necessary. I was running into the same issue recently and that worked for me:
with codecs.open( csv_file, mode='w', encoding='utf-8') as out_csv:
csv_out_file = csv.DictWriter(out_csv)
I have 3 questions I would like to ask as I am relatively new to both R and Json format. I read quite a bit of things but I don't quite understand still.
1:) Can R parse Json data when the txt file contains other irrelevant information as well?
Assuming I can't, I uploaded the text file into R and did some cleaning up. So that it will be easier to read the file.
require(plyr)
require(rjson)
small.f.2 <- subset(small.f.1, ! V1 %in% c("Level_Index:", "Feature_Type:", "Goals:", "Move_Count:"))
small.f.3 <- small.f.2[,-1]
This would give me a single column with all the json data in each line.
I tried to write new .txt file .
write.table(small.f.3, file="small clean.txt", row.names = FALSE)
json_data <- fromJSON(file="small.clean")
The problem was it only converted 'x' (first row) into a character and ignored everything else. I imagined it was the problem with "x" so I took that out from the .txt file and ran it again.
json_data <- fromJSON(file="small clean copy.txt")
small <- fromJSON(paste(readLines("small clean copy.txt"), collapse=""))
Both time worked and I manage to create a list. But it only takes the data from the first row and ignore the rest. This leads to my second question.
I tried this..
small <- fromJSON(paste(readLines("small clean copy.txt"), collapse=","))
Error in fromJSON(paste(readLines("small clean copy.txt"), collapse = ",")) :
unexpected character ','
2.) How can I extract the rest of the rows in the .txt file?
3.) Is it possible for R to read the Json data from one row, and extract only the nested data that I need, and subsequently go on to the next row, like a loop? For example, in each array, I am only interested in the Action vectors and the State Feature vectors, but I am not interested in the rest of the data. If I can somehow extract only the information I need before moving on to the next array, than I can save a lot of memory space.
I validated the array online. But the .txt file is not json formatted. Only within each array. I hope this make sense. Each row is a nested array.
The data looks something like this. I have about 65 rows (nested arrays) in total.
{"NonlightningIndices":[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15],"LightningIndices":[],"SelectedAction":12,"State":{"Features":{"Data":[21.0,58.0,0.599999964237213,12.0,9.0,3.0,1.0,0.0,11.0,2.0,1.0,0.0,0.0,0.0,0.0]}},"Actions":[{"Features":{"Data":[4.0,4.0,1.0,1.0,0.0,3.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.12213890532609,0.0,0.0,0.0,0.0,0.0,0.0,0.0,1.13055793241076,0.0,0.0,0.0,0.0,0.0,0.231325346416068,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.949158357257511,0.0,0.0,0.0,0.0,0.0,0.369666537828737,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0851765937900996,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.223409208023677,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.698640447815897,1.69496718435102,0.0,0.0,0.0,0.0,1.42312654023416,0.0,0.38394999584831,0.0,0.0,0.0,0.0,1.0,1.22164326251584,1.30980246401454,1.00411570750454,0.0,0.0,0.0,1.44306759429513,0.0,0.00568191150434618,0.0,0.0,0.0,0.0,0.0,0.0,0.157705869690127,0.0,0.0,0.0,0.0,0.102089274086033,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.37039305683305,2.64354332879095,0.0,0.456876463171171,0.0,0.0,0.208651305680117,0.0,0.0,0.0,0.0,0.0,2.0,0.0,3.46713142511126,2.26785558685153,0.284845692694476,0.29200364444299,0.0,0.562185300773834,1.79134869431988,0.423426746571872,0.0,0.0,0.0,0.0,5.06772310533214,0.0,1.95593334724537,2.08448537685298,1.22045520912269,0.251119892385839,0.0,4.86192274732091,0.0,0.186941346075472,0.0,0.0,0.0,0.0,4.37998688020614,0.0,3.04406665275463,1.0,0.49469909818283,0.0,0.0,1.57589195190525,0.0,0.0,0.0,0.0,0.0,0.0,3.55229001446173]}},......
{"NonlightningIndices":[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,24],"LightningIndices":[[15,16,17,18,19,20,21,22,23]],"SelectedAction":15,"State":{"Features":{"Data":[20.0,53.0,0.0,11.0,10.0,2.0,1.0,0.0,12.0,2.0,1.0,0.0,0.0,1.0,0.0]}},"Actions":[{"Features":{"Data":[4.0,4.0,1.0,1.0,0.0,3.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.110686363475575,0.0,0.0,0.0,0.0,0.0,0.0,0.0,1.13427913742728,0.0,0.0,0.0,0.0,0.0,0.218834141070836,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.939443046803111,0.0,0.0,0.0,0.0,0.0,0.357568892126985,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0889329732996782,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.22521492930721,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.700441220022084,1.6762090551226,0.0,0.0,0.0,0.0,1.44526456614638,0.0,0.383689214317325,0.0,0.0,0.0,0.0,1.0,1.22583659574753,1.31795156033445,0.99710368703165,0.0,0.0,0.0,1.44325394830013,0.0,0.00418600599483917,0.0,0.0,0.0,0.0,0.0,0.0,0.157518319482216,0.0,0.0,0.0,0.0,0.110244186273209,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.369899973785845,2.55505143302811,0.0,0.463342609296841,0.0,0.0,0.226088384842823,0.0,0.0,0.0,0.0,0.0,2.0,0.0,3.47842109127488,2.38476342332125,0.0698115810371108,0.276804206873942,0.0,1.53514282355593,1.77391161515718,0.421465101754304,0.0,0.0,0.0,0.0,4.45530484778828,0.0,1.43798302409155,3.46965807176681,0.468528940277049,0.259853183829217,0.0,4.86988325473155,0.0,0.190659677933533,0.0,0.0,0.963116148760181,0.0,4.29930830894124,0.0,2.56201697590845,0.593423384852181,0.46165947868584,0.0,0.0,1.59497392171253,0.0,0.0,0.0,0.0,0.0368838512398189,0.0,4.24538684327048]}},......
I would really appreciate any advice here.