I have a large csv file, containing multiple values, in the form
Date,Dslam_Name,Card,Port,Ani,DownStream,UpStream,Status
2020-01-03 07:10:01,aart-m1-m1,204,57,302xxxxxxxxx,0,0,down
I want to extract the Dslam_Name and Ani values, sort them by Dslam_name and write them to a new csv in two different columns.
So far my code is as follows:
import csv
import operator
with open('bad_voice_ports.csv') as csvfile:
readCSV = csv.reader(csvfile, delimiter=',')
sortedlist = sorted(readCSV, key=operator.itemgetter(1))
for row in sortedlist:
bad_port = row[1][:4],row[4][2::]
print(bad_port)
f = open("bad_voice_portsnew20200103SORTED.csv","a+")
f.write(row[1][:4] + " " + row[4][2::] + '\n')
f.close()
But my Dslam_Name and Ani values are kept in the same column.
As a next step I would like to count how many times the same value appears in the 1st column.
You are forcing them to be a single column. Joining the two into a single string means Python no longer regards them as separate.
But try this instead:
import csv
import operator
with open('bad_voice_ports.csv') as readfile, open('bad_voice_portsnew20200103SORTED.csv', 'w') as writefile:
readCSV = csv.reader(readfile)
writeCSV = csv.writer(writefile)
for row in sorted(readCSV, key=operator.itemgetter(1)):
bad_port = row[1][:4],row[4][2::]
print(bad_port)
writeCSV.writerow(bad_port)
If you want to include the number of times each key occurred, you can easily include that in the program, too. I would refactor slightly to separate the reading and the writing.
import csv
import operator
from collections import Counter
with open('bad_voice_ports.csv') as readfile:
readCSV = csv.reader(readfile)
rows = []
counts = Counter()
for row in readCSV:
rows.append([row[1][:4], row[4][2::]])
counts[row[1][:4]] += 1
with open('bad_voice_portsnew20200103SORTED.csv', 'w') as writefile:
writeCSV = csv.writer(writefile)
for row in sorted(rows):
print(row)
writeCSV.writerow([counts[row[0]]] + row)
I would recommend to remove the header line from the CSV file entirely; throwing away (or separating out and prepending back) the first line should be an easy change if you want to keep it.
(Also, hard-coding input and output file names is problematic; maybe have the program read them from sys.argv[1:] instead.)
So my suggestion is failry simple. As i stated in a previous comment there is good documentation on CSV read and write in python here: https://realpython.com/python-csv/
As per an example, to read from a csv the columns you need you can simply do this:
>>> file = open('some.csv', mode='r')
>>> csv_reader = csv.DictReader(file)
>>> for line in csv_reader:
... print(line["Dslam_Name"] + " " + line["Ani"])
...
This would return:
aart-m1-m1 302xxxxxxxxx
Now you can just as easilly create a variable and store the column values there and later write them to a file or just open up a new file wile reading lines and writing the column values in there. I hope this helps you.
After the help from #tripleee and #marxmacher my final code is
import csv
import operator
from collections import Counter
with open('bad_voice_ports.csv') as csv_file:
readCSV = csv.reader(csv_file, delimiter=',')
sortedlist = sorted(readCSV, key=operator.itemgetter(1))
line_count = 0
rows = []
counts = Counter()
for row in sortedlist:
Dslam = row[1][:4]
Ani = row[4][2:]
if line_count == 0:
print(row[1], row[4])
line_count += 1
else:
rows.append([row[1][:4], row[4][2::]])
counts[row[1][:4]] += 1
print(Dslam, Ani)
line_count += 1
for row in sorted(rows):
f = open("bad_voice_portsnew202001061917.xls","a+")
f.write(row[0] + '\t' + row[1] + '\t' + str(counts[row[0]]) + '\n')
f.close()
print('Total of Bad ports =', str(line_count-1))
As with this way the desired values/columns are extracted from the initial csv file and a new xls file is generated with the desired values stored in different columns and the total values per key are counted, along with the total of entries.
Thanks for all the help, please feel free for any improvement suggestions!
You can use sorted:
import csv
_h, *data = csv.reader(open('filename.csv'))
with open('new_csv.csv', 'w') as f:
write = csv.writer(f)
csv.writerows([_h, *sorted([(i[1], i[4]) for i in data], key=lambda x:x[0])])
Related
I started learning python and was wondering if there was a way to create multiple files from unique values of a column. I know there are 100's of ways of getting it done through pandas. But I am looking to have it done through inbuilt libraries. I couldn't find a single example where its done through inbuilt libraries.
Here is the sample csv file data:
uniquevalue|count
a|123
b|345
c|567
d|789
a|123
b|345
c|567
Sample output file:
a.csv
uniquevalue|count
a|123
a|123
b.csv
b|345
b|345
I am struggling with looping on unique values in a column and then print them out. Can someone explain with logic how to do it ? That will be much appreciated. Thanks.
import csv
from collections import defaultdict
header = []
data = defaultdict(list)
DELIMITER = "|"
with open("inputfile.csv", newline="") as csvfile:
reader = csv.reader(csvfile, delimiter=DELIMITER)
for i, row in enumerate(reader):
if i == 0:
header = row
else:
key = row[0]
data[key].append(row)
for key, value in data.items():
filename = f"{key}.csv"
with open(filename, "w", newline="") as f:
writer = csv.writer(f, delimiter=DELIMITER)
rows = [header] + value
writer.writerows(rows)
import csv
with open('sample.csv', newline='') as csvfile:
reader = csv.reader(csvfile)
for row in reader:
with open(f"{row[0]}.csv", 'a') as inner:
writer = csv.writer(
inner, delimiter='|',
fieldnames=('uniquevalue', 'count')
)
writer.writerow(row)
the task can also be done without using csv module. the lines of the file are read, and with read_file.read().splitlines()[1:] the newline characters are stripped off, also skipping the header line of the csv file. with a set a unique collection of inputdata is created, that is used to count number of duplicates and to create the output files.
with open("unique_sample.csv", "r") as read_file:
items = read_file.read().splitlines()[1:]
for line in set(items):
with open(line[:line.index('|')] + '.csv', 'w') as output:
output.write((line + '\n') * items.count(line))
I have a csv file where I wish to perform a sentiment analysis on this dataset containing survey data.
So far this is what I have tried (thanks to Rupin from a previous question!):
import csv
from collections import Counter
with open('myfile.csv', 'r') as f:
reader = csv.reader(f, delimiter='\t')
alist = []
iterreader = iter(reader)
next(iterreader, None)
for row in iterreader:
clean_rows = row[0].replace(",", " ").rsplit()
alist.append(clean_rows)
word_count = Counter(clean_rows)
mostWcommon = word_count.most_common(3)
print(mostWcommon)
The output is nearly okay, the only problem that I have is that Python is splitting in different rows of a list, hence I have something like this as my output:
['experienced', 1]
['experienced, 1]
['experienced, 1]
I wish to split everything in one row so that I can have the real word frequency... Any suggestions?
Thanks!
You are creating a new Counter for each row and printing only that result. If you want a total count, you can create the counter outside the rows loop and update it with data from each row:
import csv
from collections import Counter
with open('myfile.csv', 'r') as f:
reader = csv.reader(f, delimiter='\t')
alist = []
iterreader = iter(reader)
next(iterreader, None)
c = Conter()
for row in iterreader:
clean_rows = row[0].replace(",", " ").rsplit()
alist.append(clean_rows)
c.update(clean_rows)
mostWcommon = word_count.most_common(3)
print(mostWcommon)
I have a csv file looking like this
34512340,1
12395675,30
56756777,30
90673412,45
12568673,25
22593672,25
I want to be able to edit the data after the comma from python and then save the csv.
Does anybody know how I would be able to do this?
This bit of code below will write a new line, but not edit:
f = open("stockcontrol","a")
f.write(code)
Here is a sample, which adds 1 to the second column:
import csv
with open('data.csv') as infile, open('output.csv', 'wb') as outfile:
reader = csv.reader(infile)
writer = csv.writer(outfile)
for row in reader:
# Transform the second column, which is row[1]
row[1] = int(row[1]) + 1
writer.writerow(row)
Notes
The csv module correctly parses the CSV file--highly recommended
By default, each row will be parsed as text, what is why I converted into integer: int(row[1])
Update
If you really want to edit the file "in place", then use the fileinput module:
import fileinput
for line in fileinput.input('data.csv', inplace=True):
fields = line.strip().split(',')
fields[1] = str(int(fields[1]) + 1) # "Update" second column
line = ','.join(fields)
print line # Write the line back to the file, in place
You can use python pandas to edit the column you want for e.g increase the column number by n:
import pandas
data_df = pandas.read_csv('input.csv')
data_df = data_df['column2'].apply(lambda x: x+n)
print data_df
for adding 1 replace n by 1.
I am probably making a stupid mistake, but I can't find where it is. I want to count the number of lines in my csv file. I wrote this, and obviously isn't working: I have row_count = 0 while it should be 400. Cheers.
f = open(adresse,"r")
reader = csv.reader(f,delimiter = ",")
data = [l for l in reader]
row_count = sum(1 for row in reader)
print row_count
with open(adresse,"r") as f:
reader = csv.reader(f,delimiter = ",")
data = list(reader)
row_count = len(data)
You are trying to read the file twice, when the file pointer has already reached the end of file after saving the data list.
First you have to open the file with open
input_file = open("nameOfFile.csv","r+")
Then use the csv.reader for open the csv
reader_file = csv.reader(input_file)
At the last, you can take the number of row with the instruction 'len'
value = len(list(reader_file))
The total code is this:
input_file = open("nameOfFile.csv","r+")
reader_file = csv.reader(input_file)
value = len(list(reader_file))
Remember that if you want to reuse the csv file, you have to make a input_file.fseek(0), because when you use a list for the reader_file, it reads all file, and the pointer in the file change its position
If you are working with python3 and have pandas library installed you can go with
import pandas as pd
results = pd.read_csv('f.csv')
print(len(results))
I would consider using a generator. It would do the job and keeps you safe from MemoryError of any kind
def generator_count_file_rows(input_file):
for row in open(input_file,'r'):
yield row
And then
for row in generator_count_file_rows('very_large_set.csv'):
count+=1
The important stuff is hidden in comments section of solution which is marked correct.
Re-sharing Erdős-Bacon's solution here for better visibility.
Why ?
Because: It saves lot of memory without having to create list.
So I think it is better do this way
def read_raw_csv(file_name):
with open(file_name, 'r') as file:
csvreader = csv.reader(file)
# count number of rows
entry_count = sum(1 for row in csvreader)
print(entry_count-1) # -1 is for discarding header row.
Checkout this link for more info
# with built in libraries
opened_file = open('f.csv')
from csv import reader
read_file = reader(opened_file)
apps_data = list(read_file)
rowcount = len(apps_data) #which incudes header row
print("Total rows incuding header: " + str(rowcount))
Simply Open the csv file in Notepad++. It shows the total row count in a jiffy. :)
Or
in cmd prompt , Provide file path and key in the command
find \c \v "some meaningless string" Filename.csv
I need a way to get a specific item(field) of a CSV. Say I have a CSV with 100 rows and 2 columns (comma seperated). First column emails, second column passwords. For example I want to get the password of the email in row 38. So I need only the item from 2nd column row 38...
Say I have a csv file:
aaaaa#aaa.com,bbbbb
ccccc#ccc.com,ddddd
How can I get only 'ddddd' for example?
I'm new to the language and tried some stuff with the csv module, but I don't get it...
import csv
mycsv = csv.reader(open(myfilepath))
for row in mycsv:
text = row[1]
Following the comments to the SO question here, a best, more robust code would be:
import csv
with open(myfilepath, 'rb') as f:
mycsv = csv.reader(f)
for row in mycsv:
text = row[1]
............
Update: If what the OP actually wants is the last string in the last row of the csv file, there are several aproaches that not necesarily needs csv. For example,
fulltxt = open(mifilepath, 'rb').read()
laststring = fulltxt.split(',')[-1]
This is not good for very big files because you load the complete text in memory but could be ok for small files. Note that laststring could include a newline character so strip it before use.
And finally if what the OP wants is the second string in line n (for n=2):
Update 2: This is now the same code than the one in the answer from J.F.Sebastian. (The credit is for him):
import csv
line_number = 2
with open(myfilepath, 'rb') as f:
mycsv = csv.reader(f)
mycsv = list(mycsv)
text = mycsv[line_number][1]
............
#!/usr/bin/env python
"""Print a field specified by row, column numbers from given csv file.
USAGE:
%prog csv_filename row_number column_number
"""
import csv
import sys
filename = sys.argv[1]
row_number, column_number = [int(arg, 10)-1 for arg in sys.argv[2:])]
with open(filename, 'rb') as f:
rows = list(csv.reader(f))
print rows[row_number][column_number]
Example
$ python print-csv-field.py input.csv 2 2
ddddd
Note: list(csv.reader(f)) loads the whole file in memory. To avoid that you could use itertools:
import itertools
# ...
with open(filename, 'rb') as f:
row = next(itertools.islice(csv.reader(f), row_number, row_number+1))
print row[column_number]
import csv
def read_cell(x, y):
with open('file.csv', 'r') as f:
reader = csv.reader(f)
y_count = 0
for n in reader:
if y_count == y:
cell = n[x]
return cell
y_count += 1
print (read_cell(4, 8))
This example prints cell 4, 8 in Python 3.
There is an interesting point you need to catch about csv.reader() object. The csv.reader object is not list type, and not subscriptable.
This works:
for r in csv.reader(file_obj): # file not closed
print r
This does not:
r = csv.reader(file_obj)
print r[0]
So, you first have to convert to list type in order to make the above code work.
r = list( csv.reader(file_obj) )
print r[0]
Finaly I got it!!!
import csv
def select_index(index):
csv_file = open('oscar_age_female.csv', 'r')
csv_reader = csv.DictReader(csv_file)
for line in csv_reader:
l = line['Index']
if l == index:
print(line[' "Name"'])
select_index('11')
"Bette Davis"
Following may be be what you are looking for:
import pandas as pd
df = pd.read_csv("table.csv")
print(df["Password"][row_number])
#where row_number is 38 maybe
import csv
inf = csv.reader(open('yourfile.csv','r'))
for row in inf:
print row[1]