I have many text files. I tried to convert the txt files into a single CSV file, but it is taking a huge time. I put the code on run mode at night and I slept, it processed only 4500 files, but still morning it is running.
There is any way to fast way to convert the text files into csv?
Here is my code:
import pandas as pd
import os
import glob
from tqdm import tqdm
# create empty dataframe
csvout = pd.DataFrame(columns =["ID","Delivery_person_ID" ,"Delivery_person_Age" ,"Delivery_person_Ratings","Restaurant_latitude","Restaurant_longitude","Delivery_location_latitude","Delivery_location_longitude","Order_Date","Time_Orderd","Time_Order_picked","Weather conditions","Road_traffic_density","Vehicle_condition","Type_of_order","Type_of_vehicle", "multiple_deliveries","Festival","City","Time_taken (min)"])
# get list of files
file_list = glob.glob(os.path.join(os.getcwd(), "train/", "*.txt"))
for filename in tqdm(file_list):
# next file/record
mydict = {}
with open(filename) as datafile:
# read each line and split on " " space
for line in tqdm(datafile):
# Note: partition result in 3 string parts, "key", " ", "value"
# array slice third parameter [::2] means steps=+2
# so only take 1st and 3rd item
name, var = line.partition(" ")[::2]
mydict[name.strip()] = var.strip()
# put dictionary in dataframe
csvout = csvout.append(mydict, ignore_index=True)
# write to csv
csvout.to_csv("train.csv", sep=";", index=False)
Here is my example text file.
ID 0xb379
Delivery_person_ID BANGRES18DEL02
Delivery_person_Age 34.000000
Delivery_person_Ratings 4.500000
Restaurant_latitude 12.913041
Restaurant_longitude 77.683237
Delivery_location_latitude 13.043041
Delivery_location_longitude 77.813237
Order_Date 25-03-2022
Time_Orderd 19:45
Time_Order_picked 19:50
Weather conditions Stormy
Road_traffic_density Jam
Vehicle_condition 2
Type_of_order Snack
Type_of_vehicle scooter
multiple_deliveries 1.000000
Festival No
City Metropolitian
Time_taken (min) 33.000000
CSV is a very simple data format for which you don't need any sophisticated tools to handle. Just text and separators.
In your hopefully simple case there is no need to use pandas and dictionaries.
Except your datafiles are corrupt missing some columns or having some additional columns to skip. But even in this case you can handle such issues better within your own code so you have more control over it and are able to get results within seconds.
Assuming your datafiles are not corrupt having all columns in the right order with no missing columns or having additional ones (so you can rely on their proper formatting), just try this code:
from time import perf_counter as T
sT = T()
filesProcessed = 0
columns =["ID","Delivery_person_ID" ,"Delivery_person_Age" ,"Delivery_person_Ratings","Restaurant_latitude","Restaurant_longitude","Delivery_location_latitude","Delivery_location_longitude","Order_Date","Time_Orderd","Time_Order_picked","Weather conditions","Road_traffic_density","Vehicle_condition","Type_of_order","Type_of_vehicle", "multiple_deliveries","Festival","City","Time_taken (min)"]
import glob, os
file_list = glob.glob(os.path.join(os.getcwd(), "train/", "*.txt"))
csv_lines = []
csv_line_counter = 0
for filename in file_list:
filesProcessed += 1
with open(filename) as datafile:
csv_line = ""
for line in datafile.read().splitlines():
# print(line)
var = line.partition(" ")[-1]
csv_line += var.strip() + ';'
csv_lines.append(str(csv_line_counter)+';'+csv_line[:-1])
csv_line_counter += 1
with open("train.csv", "w") as csvfile:
csvfile.write(';'+';'.join(columns)+'\n')
csvfile.write('\n'.join(csv_lines))
eT = T()
print(f'> {filesProcessed=}, {(eT-sT)=:8.6f}')
I guess you will get the result in a speed beyond your expectations (in seconds, not minutes or hours)
On my computer, estimating from processing time of 100 files the time required for 50.000 files will be about 3 seconds.
I could not replicate. I took the example data file and created 5000 copies of it. Then I ran your code using tqdm and without. The below shows without:
import time
import csv
import os
import glob
import pandas as pd
from tqdm import tqdm
csvout = pd.DataFrame(columns =["ID","Delivery_person_ID" ,"Delivery_person_Age" ,"Delivery_person_Ratings","Restaurant_latitude","Restaurant_longitude","Delivery_location_latitude","Delivery_location_longitude","Order_Date","Time_Orderd","Time_Order_picked","Weather conditions","Road_traffic_density","Vehicle_condition","Type_of_order","Type_of_vehicle", "multiple_deliveries","Festival","City","Time_taken (min)"])
file_list = glob.glob(os.path.join(os.getcwd(), "sample_files/", "*.txt"))
t1 = time.time()
for filename in file_list:
# next file/record
mydict = {}
with open(filename) as datafile:
# read each line and split on " " space
for line in datafile:
# Note: partition result in 3 string parts, "key", " ", "value"
# array slice third parameter [::2] means steps=+2
# so only take 1st and 3rd item
name, var = line.partition(" ")[::2]
mydict[name.strip()] = var.strip()
# put dictionary in dataframe
csvout = csvout.append(mydict, ignore_index=True)
# write to csv
csvout.to_csv("train.csv", sep=";", index=False)
t2 = time.time()
print(t2-t1)
The times I got where:
tqdm 33 seconds
no tqdm 34 seconds
Then I ran using the csv module:
t1 = time.time()
with open('output.csv', 'a', newline='') as csv_file:
columns =["ID","Delivery_person_ID" ,"Delivery_person_Age" ,"Delivery_person_Ratings","Restaurant_latitude","Restaurant_longitude","Delivery_location_latitude","Delivery_location_longitude","Order_Date","Time_Orderd","Time_Order_picked","Weather conditions","Road_traffic_density","Vehicle_condition","Type_of_order","Type_of_vehicle", "multiple_deliveries","Festival","City","Time_taken (min)"]
mydict = {}
d_Writer = csv.DictWriter(csv_file, fieldnames=columns, delimiter=',')
d_Writer.writeheader()
for filename in file_list:
with open(filename) as datafile:
for line in datafile:
name, var = line.partition(" ")[::2]
mydict[name.strip()] = var.strip()
d_Writer.writerow(mydict)
t2 = time.time()
print(t2-t1)
The time for this was:
csv 0.32231569290161133 seconds.
Try it like this.
import glob
with open('my_file.csv', 'a') as csv_file:
for path in glob.glob('./*.txt'):
with open(path) as txt_file:
txt = txt_file.read() + '\n'
csv_file.write(txt)
I have to read a CSV file N lines at a time.
csv_reader = csv.reader(csv_file, delimiter=',')
line_count = 0
for row in csv_reader:
print row
I know I can loop N times at a time, build a list of list and process that way.
But is there a simpler way of using csv_reader so that I read n lines at a time.
Hi I don't think that you'll be able to do that without a loop with csv package.
You should use pandas (pip install --user pandas) instead:
import pandas
df = pandas.read_csv('myfile.csv')
start = 0
step = 2 # Your 'N'
for i in range(0, len(df), step):
print(df[i:i+step])
start = i
Pandas has a chunksize option to their read_csv() method and I would probably explore that option.
If I was going to do it myself by hand, I would probably do something like:
import csv
def process_batch(rows):
print(rows)
def get_batch(reader, batch_size):
return [row for _ in range(batch_size) if (row:=next(reader, None))]
with open("data.csv", "r") as file_in:
reader = csv.reader(file_in)
while batch := get_batch(reader, 5):
process_batch(batch)
I'm using pandas to open a CSV file that contains data from spotify, meanwhile, I have a txt file that contains various artists names from that CSV file. What I'm trying to do is get the value from each row of the txt and automatically search them in the function I've done.
import pandas as pd
import time
df = pd.read_csv("data.csv")
df = df[['artists', 'name', 'year']]
def buscarA():
start = time.time()
newdf = (df.loc[df['artists'].str.contains(art)])
stop = time.time()
tempo = (stop - start)
print (newdf)
e = ('{:.2f}'.format(tempo))
print (e)
with open("teste3.txt", "r") as f:
for row in f:
art = row
buscarA()
but the output is always the same:
Empty DataFrame
Columns: [artists, name, year]
Index: []
The problem here is that when you read the lines of your file in Python, it also gets the line break per row so that you have to strip it off.
Let's suppose that the first line of your teste3.txt file is "James Brown". It'd be read as "James Brown\n" and not recognized in the search.
Changing the last chunk of your code to:
with open("teste3.txt", "r") as f:
for row in f:
art = row.strip()
buscarA()
should work.
I am trying to import data from a large csv file 15GB+. I have to select few columns with specific values (there are over 50 columns) but as an example. I have used
df=pd.read_csv('filename.csv', nrows=10000, usecols=['ID', State'])
Is there a way where I can specify something like that:
df=pd.read_csv('filename.csv', nrows=10000, usecols=['ID', 'State'='abc'])
Can't find any option to do that
There's no option to filter rows like that while reading csv files.
What you can do is create an iterator then apply your filter to each chunk then concat the chunks. It would look something like:
iterable = pd.read_csv('filename.csv', usecols=['ID', 'State'], iterator=True, chunksize=10000)
df = pd.concat([chunk[chunk['State'] == 'abc'] for chunk in iterable])
Assuming that the resulting DataFrame for a selection where 'State' == 'abc' is small enough to be accommodated in RAM, you could extract those from the csv as follows. df is the resultant DataFrame.
import pandas as pd
inPath = 'filename.csv'
chunkSize = 10000 #size of chunks relies on your available memory
tmpDf = pd.read_csv(inPath,chunksize=chunkSize,
usecols=['ID', 'State'])
for chunk in tmpDf:
try:
df
except NameError:
df = tmpDf[tmpDf['State'] == 'abc']
else:
df = pd.concat([df, tmpDf[tmpDf['State'] == 'abc']])
I have a csv file containing 60,000 entries. I read them and store in a nested list like this:
entries = []
with open('mnist_train.csv', 'r') as f:
mycsv = csv.reader(f)
for row in mycsv:
entries.append(row)
Instead of reading all 60,000 how would I read only the first thousand entries?
I tried this without success:
entries = []
with open('mnist_train.csv', 'r') as f:
mycsv = csv.reader(f)
for row in mycsv[:1000]:
entries.append(row)
As you've discovered a csv.reader does not support slicing. You can use itertools.islice() to accomplish this with objects that are iterable. E.g.,
import itertools
entries = []
with open('mnist_train.csv', 'r') as f:
mycsv = csv.reader(f)
for row in itertools.islice(mycsv, 1000):
entries.append(row)
You can use the pandas library-
import pandas as pd
data = pd.read_csv('path/to/your/file.csv',nrows=1000)
data_list = data.values.tolist() #creates a list of the first 1000 rows (excludes header)