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+--- Thread: Avoiding empty line in writing process csv file (/thread-18244.html)
Avoiding empty line in writing process csv file - go127a - May-10-2019
Hallo, I have done some calculation on csv file. However, the output csv, after writing process added one empty line at the end of results.
My question is how can I remove or avoid that line.
the code is here:
import csv
from statistics import mean
import itertools
from collections import OrderedDict
def calculate_average_of_averages(input_file_name, output_file_name):
with open ('grades.csv', 'r') as input_file_name:
reader=csv.reader(input_file_name)
val1=[]
key=list()
data=[]
for row in reader:
l2 = []
k = row[0]
grades=[int(num) for num in row[1:]]
l2.append(float(mean(grades)))
key.append(k) #making a name -key- list
val1.append(l2) #making a value list
value = list(itertools.chain.from_iterable(val1)) #making a simple list from list of list in value
value=[float(i) for i in value] ##changing string to float in values
dictionary = dict(zip(key, value))
findic=OrderedDict(sorted(dictionary.items(), key=lambda t: t[1])) ##making a sorted list by OrderedDict
lv=[]
for item in findic.values():
lv.append(item)
data.append(float(mean(value)))
with open('grades.csv', 'w', newline='') as output_file_name:
writer = csv.writer(output_file_name)
writer.writerows(map(lambda x: [x], data))
output_file_name.close()
calculate_average_of_averages('input.csv','output.csv')the correct output is:Quote:8.401530612244898
but now I got the csv file like:
Quote:8.401530612244898
(this line is empty but exist)
RE: Avoiding empty line in writing process csv file - perfringo - May-10-2019
Maybe you could ask yourself a question - if you write-append to an existing csv file, where do you want your first line to be written? On the same line as last line in file or on a new line after last line?
RE: Avoiding empty line in writing process csv file - go127a - May-10-2019
its correct there is no problem with writing, the csv file should be rewrite by the results, but the problem is, I have two line in the output (one extra line, which is unnecessary)
the problem produced by 'writerows' i know that, but I can not find, how can I write the output except 'writerows'
csv writing process.
https://docs.python.org/3/library/csv.html
RE: Avoiding empty line in writing process csv file - perfringo - May-10-2019
Unfortunately you didn't ask the question I suggested.
How could (any) program know when and where row ends? There is newline at the end of every row. If you write a row it will end with newline. What will happen if there is newline at the end of last row?
RE: Avoiding empty line in writing process csv file - go127a - May-10-2019
I have used below code for writing, is it correct? (i mean is there any easier way?)
for item in data:
dataf=str(item)
with open('grades.csv', 'w', newline='') as output_file_name:
output_file_name.write(dataf)
output_file_name.close()