Working with CSV files in Python
Here we will discuss how to load and parse a CSV file in Python.
First of all, what is a CSV ?
CSV (Comma Separated Values) is a simple file format used to store tabular data, such as a spreadsheet or database. A CSV file stores tabular data (numbers and text) in plain text. Each line of the file is a data record. Each record consists of one or more fields, separated by commas. The use of the comma as a field separator is the source of the name for this file format.
For working CSV files in python, there is an inbuilt module called csv.
# importing csv module
Steps to follow:
|1.||import the csv module|
|2.||create the fields for the csv file|
create the rows of data to be stored in the csv file.(input of values can also be taken and stored in the form of a list)
|4||plan the filename of csv file.|
|5.||open the csv file in write mode (“w”).|
|6.|| create a csv writer object
csvwriter = csv.writer(csvfile)
|7.|| writing the fields in csv file
|8.|| writing the data rows
Python program to create a CSV file named “student.csv”, to store Roll,Name and Per of students.
#csv file example #to create a csv file # importing the csv module import csv # field names fields = ['Roll', 'Name', 'Per'] # data rows of csv file rows = [ ['101', 'Nikhil', '99'], ['102', 'Sanchit', '98'], ['103', 'Aditya', '98'], ['104', 'Sagar', '87'], ['105', 'Prateek', '88'], ] # name of csv file filename = "student.csv" # writing to csv file with open(filename, 'w') as csvfile: # creating a csv writer object csvwriter = csv.writer(csvfile) # writing the fields csvwriter.writerow(fields) # writing the data rows csvwriter.writerows(rows)
After the execution of the above file, a csv file named “student.csv” gets created. It is an excel file.
Python program read the contents of CSV file named “student.csv”, and display Roll,Name and Per of students.
# importing csv module import csv # csv file name filename = "student.csv" # initializing the titles and rows list fields =  rows =  # reading csv file with open(filename, 'r') as csvfile: # creating a csv reader object csvreader = csv.reader(csvfile) # extracting field names through first row fields = next(csvreader) # extracting each data row one by one for row in csvreader: rows.append(row) # get total number of rows print("Total no. of rows: %d"%(csvreader.line_num)) # printing the field names print('Field names are:' + ', '.join(field for field in fields)) # printing first 5 rows print('\nFirst 15 rows are:\n') for row in rows[:15]: # parsing each column of a row for col in row: print(col,end=' ') print('\n')
Total no. of rows: 12 Field names are:Roll, Name, Per First 15 rows are: 101 Nikhil 99 102 Sanchit 98 103 Aditya 98 104 Sagar 87 105 Prateek 88 >>>