Python read and update csv file
View Discussion Show Improve Article Save Article View Discussion Improve Article Save Article Prerequisites: Pandas In this article, we will discuss ways in which the value(s) of a column can be updated. The best and the optimal way to update any column value of a CSV is to use the Pandas Library and the DataFrame functions. Link for the CSV file in use – Click here Method 1Approach
to_csv()method converts the Data Frame into CSV data as the output is returned to the file, it takes the file object or the file name as the parameter and the index=False should be mentioned so that the indices are not written into the CSV file. But this method is very tedious and is not reliable when you want to update similar values that are occurring multiple times. Details in the file before updating: Example: Python3
Details after updating: Method 2:Approach
The replace() method is useful when we have to update the data that is occurring multiple number of time. We simply just have to specify the column name and need to pass the values as a dictionary into the replace() method which is in the form of key and value pair, the key will have the previous data of the column and value will have the data to be updated with. Before updating column data/value: Example: Python3
After updating column data/value: Method 3:In this method, we are employing csv module which is a dedicated module centrally created for reading, writing and updating csv files. Approach:
File before update: Program: Python3
Output: How do I update an existing CSV file in Python?“how to update data in csv file using python” Code Answer's. from tempfile import NamedTemporaryFile.. import shutil.. import csv.. filename = 'my.csv'. tempfile = NamedTemporaryFile(mode='w', delete=False). fields = ['ID', 'Name', 'Course', 'Year']. How do you update data in a CSV file?To run the update:. In the toolbar, click your username. A drop-down list appears.. In the drop-down list, select Administration. ... . Click the Import tab. ... . In the area relevant to the type of data you are importing, click Select a File.. Select the desired CSV file. ... . Click Import.. How do I read and append a CSV file in Python?If you need to append row(s) to a CSV file, replace the write mode ( w ) with append mode ( a ) and skip writing the column names as a row ( writer. writerow(column_name) ). You'll see below that Python creates a new CSV file (demo_csv1.
How do I change the value of a column in a CSV file in Python?Change cell value of a CSV file by row/column number
It changes the value of the cell at row number N and column number M. Once the DataFrame is modified, we can save the DataFrame to the same CSV file using the to_csv() function cell value in the CSV file will be updated.
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