But if we have a huge number of columns in our csv file and most of them are empty then creating empty entries for each of them will be a hectic task. Then adds the content of list as a new row in the end of csv file. df.append() will append/combine data from one file to another. Search for jobs related to Python append one file to another or hire on the world's largest freelancing marketplace with 18m+ jobs. Set in python provides another function update() to add the elements to the set i.e. In this article, we will discuss how to append a row to an. Python: How to insert lines at the top of a file? You don't need to use pandas. Python version in my environment # python3 --version Python 3.6.8 . how about changing to append mode 'a' instead of 'w' Also looks like you have same file open twice, line 26 and 28 for writing. The file is created if it does … As new row is added in the csv file, now close the file object. It added the list as row in the existing csv file ‘students.csv’. The values of individual columns are separated by a separator symbol - a comma (,), a semicolon (;) or another symbol. Using the Pandas library in Python, we can get data from a source Excel file and insert it into a new Excel file and then name and save that file. A CSV file stores tabular data (numbers and text) in plain text. The above steps will append our dictionary as a new row in the csv. your coworkers to find and share information. ... Another idea I had was to create one CSV file at the beginning through pandas, and then append that CSV file as my code keeps looping, but I'm unsure of how to do that. Extend has time complexity of O(k). Example: – import csv with open(“you excel file name”, “read cmd”) as y: filereader=csv.reader(y) # print(“complete reading”) Each record consists of one or more fields, separated by commas. Pandas is one of those packages and makes importing and analyzing data much easier.. Pandas dataframe.append() function is used to append rows of other dataframe to the end of the given dataframe, returning a new dataframe object. In this tutorial, we shall learn the syntax of extend() function and how to use this function to append a list to other list. existing csv file using csv module’s reader / writer & DictReader / DictWriter classes. But they are some scenarios which makes one solution better than other. Making statements based on opinion; back them up with references or personal experience. Each line of the file is a data record. Required fields are marked *. pd.read_excel() will read Excel data into Python and store it as a pandas DataFrame object. CSV file stores tabular data (numbers and text) in plain text. Strengthen your foundations with the Python Programming Foundation Course and learn the basics. I have looked at many solutions for this but cannot find one that works for what I want to do. Join a list of 2000+ Programmers for latest Tips & Tutorials, Append/ Add an element to Numpy Array in Python (3 Ways), Count number of True elements in a NumPy Array in Python, Count occurrences of a value in NumPy array in Python, Mysql: select rows with MAX(Column value), DISTINCT by another column, MySQL select row with max value for each group. Why does nslookup -type=mx YAHOO.COMYAHOO.COMOO.COM return a valid mail exchanger? How are Presidential candidates, who run for the party ticket in Primaries and Caucuses, shortlisted? Adding multiple elements to the set. One of the problems with automatically detecting csv files is that the names are dynamically generated. Adding multiple elements to the set. After appending, it returns a new DataFrame object. To this, you have to use concate() method. In this article we will discuss how to append elements at the end on a Numpy Array in python. Well the same logic applies here. The file is created if it does … I am writing a script that takes one CSV file searches for a value in another CSV file then writes an output depending on the result it finds. Attention geek! Whereas, csv.writer class in python’s csv module provides a mechanism to write a list as a row in the csv file. site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. Why aren't "fuel polishing" systems removing water & ice from fuel in aircraft, like in cruising yachts? How to detect real C64, TheC64, or VICE emulator in software? To make our life easier, we have created a separate function that performs the above steps. If any element is missing like in the above example, then we should pass empty strings in the list like this. How to write graph coordinates in German? So, let’s discuss both of them one by one. Simply append one csv to another: Thanks for contributing an answer to Stack Overflow! To learn more, see our tips on writing great answers. For working CSV files in python, there is an inbuilt module called csv. A CSV file is a bounded text format which uses a comma to separate values. Where k is the length of list which need to be added. Python: Tips of the Day. We used + operator earlier to print variables with strings. default_text)) print('Use DictReader DictWriter to add a column with same values to an existing csv') header_of_new_col = 'Address'. It also allows us to read an external CSV or excel file, import DataFrames, work on them, and save them back. of columns from another table by joining on some sort of relationship which exists within a table or appending two tables which is adding one or more table over another table with keeping the same order of … If there are missing entries in our dictionary or even items are in different order, in both the cases DictWriter class will automatically handle it and will add only given columns in the new row. Nigel Blanchard-August 7th, 2019 at 9:33 pm none Comment author #26915 on Python : How to copy files from one location to another using shutil.copy() by thispointer.com Very fine site I am a retired chartered surveyor in UK and learning Python and it you are one of few programming sites that takes a basic explanation to a more advanced example within a few easy to follow steps. - Topic in the Software Development forum contributed by rajeshwari_ib Append has constant time complexity i.e.,O(1). Stack Overflow for Teams is a private, secure spot for you and But what if our row has missing entries ? Pandas DataFrame append () Method in Python By Ankit Lathiya Last updated Jun 2, 2020 Pandas DataFrame append () method is used to append rows of one DataFrame to the end of the other DataFrame. PowerShell Microsoft Technologies Software & Coding To append the data into CSV file you need to use – Append parameter while exporting to the CSV … To make the process simple, we have created a separate function with the above steps. To this, you have to use concate() method. To save us from this hectic work, csv module provides an another class DictWriter. This is the basic syntax: Tip: These are the two most commonly used arguments to call this function. This function accepts a csv file name and a list of elements as arguments. Let’s see how we can use it. Can I repeatedly Awaken something in order to give it a variety of languages? Hey, Scripting Guy! Are there 300,000 items in the average American household, and 10,000 items in the average European household? I have it working, but it is very inefficient because it is looping through the 2 sets of data until it finds a result. numpy.append() Python’s Numpy module provides a function to append elements to the end of a Numpy Array. Let’s see how to use it for appending a new row in csv. This writer object has a function writerow() , pass the list to it and it will add list’s contents as a new row in the associated csv file. Python provides a csv module for reading and writing csv files. After that I can do anything from that dataset. The definition of these access modes are as follows: Append Only (‘a’): Open the file for writing. Drawing a backward arrow in a flow chart using TikZ, Improve performance of index reorganize on volatile table. The use of the comma as a field separator is the source of the name for this file format. Think about copying a block of data from one Excel file and pasting it into another. Append the contents of the second file to the first file using the write () function. motion_detection.ipynb ... # Creating a CSV file in which time of movements will be saved df.to_csv ... How do I append one string to another in Python? Simply append one csv to another: with open('original.csv', 'r') as f1: original = f1.read() with open('all.csv', 'a') as f2: f2.write('\n') f2.write(original) Output: mRNA-1273 vaccine: How do you say the “1273” part aloud? Each line of the file is a data record. We intend to append two different variables into an existing string As new line is added in the csv file, now close the file object. Did human computers use floating-point arithmetics? Ask Question Asked 3 years, 1 month ago. You can also assign values to multiple variables in one line. Summary: Learn how to use Windows PowerShell to easily append one CSV file to another CSV file. Therefore we will be using the .csv file extension name and a python package called glob to automatically detect all of the files ending with a . This is a text format intended for the presentation of tabular data. Is there a way to append a .csv file? Visualize data from CSV file in Python; Copy data from one excel file to another in python. Be aware that this method reads only the first tab/sheet of the Excel file by default. We can append a new line in csv by using either of them. Python: How to append a new row to an existing csv file? csv’s writer class has no functionality to check if any of the intermediate column values are missing in the list or if they are in the correct order. Why hasn't JPE formally retracted Emily Oster's article "Hepatitis B and the Case of the Missing Women" (2005)? So, DictWriter added a row with these columns only and that too in correct position. Where k is the length of list which need to be added. One of the most important functions that you will need to use as you work with files in Python is open(), a built-in function that opens a file and allows your program to use it and work with it. Keys in this dictionary matches with the column names in csv file. As in dictionary their were values for keys ‘Id’, ‘Name’ & ‘Session’ only. 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Python is a great language for doing data analysis, primarily because of the fantastic ecosystem of data-centric python packages. Reposition the cursor of the files at the beginning using the seek () function. Append a list as new row to an old csv file using csv.writer(). def loc_id(city, county, state): return city, county, state x,y,z = loc_id("AG", "IN", "UP") print(y) Output: IN Asking for help, clarification, or responding to other answers. This seems like it should be much shorter but I had to go this route to get it to work. Does Python have a string 'contains' substring method? I need to be able to append one comma separated value (CSV) to another CSV file and create a new CSV … The following is my code but I'm having trouble with copying only the second row to exclude the header plus it is appending with a skipped row. I have a csv file and I want to transfer the raw data without the headers to a new csv file and have the rows and columns the same as the original. For example, if we have this file: And we want to add a new line to it, we can open it using the "a" mode (append) and then, call the write() method, passing the content that we want to append as argument. This function accepts 3 arguments i.e. How to iterate over rows in a DataFrame in Pandas, How to select rows from a DataFrame based on column values. Append has constant time complexity i.e.,O(1). Hi all, How to write one file to the end of other file using python. Data in the form of tables is also called CSV (comma separated values) - literally "comma-separated values." Open our csv file in append mode and create a file object, Pass the file object & a list of csv column names to the csv.DictWriter(), we can get a DictWriter class object. Adding a dictionary to another dictionary; Add items to a dictionary in a loop; ... function or [] operator. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. It's free to sign up and bid on jobs. if some entries are missing in the list ? The definition of these access modes are as follows: Append Only (‘a’): Open the file for writing. If you pass extra name in this list, it will add another new column with that name with new values. One of the problems with automatically detecting csv files is that the names are dynamically generated. Use the above created function to append a dictionary as a row in our csv file ‘students.csv’. Therefore while adding a list as a row using csv.writer() we need to make sure that all elements are provided and in correct order. Python: Add a column to an existing CSV file, Python: Read a CSV file line by line with or without header, Python: Read CSV into a list of lists or tuples or dictionaries | Import csv to list. Python – Append List to Another List – extend To append a list to another list, use extend function on the list you want to extend and pass the other list as argument to extend function. Python: How to delete specific lines in a file in a memory-efficient way? Does Python have a ternary conditional operator? "Appending" means adding something to the end of another thing. Python: Function return assignments. Example 1: Append a Pandas DataFrame to Another. The above steps will append out list as a row in the csv. Column with missing entries will be empty. csvtool pastecol 2 2 file1.csv file2.csv If you have not installed csvtool already in the past, you have to sudo apt-get install csvtool.. From the docs: For writing csv files, it has two different classes i.e. How to append string in Python. It will just add the items in the list as column values of the last row in sequential order. import pandas as pd import numpy as np import os, collections, csv from os.path import basename. What is the correct way to say I had to move my bike that went under the car in a crash? I have a script which compares 2 csv files and outputs the data to a new CSV file. Python – Append content of one text file to another Last Updated : 29 Dec, 2020 Having two file names entered from users, the task is to append the … pass our dictionary to this function, it adds them as a new row in the associated csv file. Your email address will not be published. Here is another beautiful one. Isn't there code in python 3.6 to append a .csv file like you would a .tx csv module provides a class DictWriter, which can write dictionaries into csv file as rows. The "a" mode allows you to open a file to append some content to it. The DataFrame append() function returns a new DataFrame object and doesn’t change the source objects. Need to append some data of 1 csv to another Welcome › Forums › General PowerShell Q&A › Need to append some data of 1 csv to another This topic has 6 replies, 3 voices, and was last updated 5 years, 5 months ago by Python, how to repeatedly append to CSV file created by pandas for storing weather data. Each record consists of one or more fields, separated by commas. In this article, we will discuss how to append a row to an existing csv file using csv module’s reader / writer & DictReader / DictWriter classes. Hello. Python – Append List to Another List – extend() To append a list to another list, use extend() function on the list you want to extend and pass the other list as argument to extend() function.. Suppose I have two sheets of the same dataset and I want to work on a single sheet. Set in python provides another function update() to add the elements to the set i.e. Contents of the csv file ‘students.csv’ are. In order to append a new line to the existing file, open the file in append mode, by using either 'a' or 'a+' as the access mode. If you use pandas, you can append your dataframes to an existing CSV file this way: df.to_csv('log.csv', mode='a', index=False, header=False) With mode='a' we ensure that we append, rather than overwrite, and with header=False we ensure that we append only the values of df rows, rather than header + values. ... Browse other questions tagged python csv … Learn how your comment data is processed. reader (open ('civil-war-battles.csv', 'r')) for row in inputfile: print row Podcast 301: What can you program in just one tweet? We have now imported: pandas — (Python for Data Analysis Library) — has libraries that help you carry out data analysis numpy — (A library for playing around with numbers in Python) — now we can leverage the libraries and do the stuff we want!. In this example we define a new list new_colums and store the new column name. Presenting you “CSV Files with Python - Read, Write & Append”.Python is simple enough for beginners, powerful enough for the pros. Your email address will not be published. Fortunately, Python makes it very easy to read and write CSV files that can do a lot of hard work for us. Open the first file in append mode and the second file in read mode. What do this numbers on my guitar music sheet mean. One liners are huge in Python, which makes the syntax so attractive and practical sometimes. Steps will be to append a column in csv file are, Example 1: Sometimes you can change the meaning of a word by removing the suffix and appending […] Code faster with the Kite plugin for your code editor, featuring Line-of-Code Completions and cloudless processing. Here we are using one simple and tricky method that How to copy data from one excel sheet to another using python. In many "real world" situations, the data that we want to use come in multiplefiles. It will just add the items in the list as column values of the last row in sequential order. csv module provides a class writer, which can write lists into csv file as rows. Then appends the content of dictionary as a new row in the end of csv file. df.append() will append/combine data from one file to another. 0 votes. Now, we will iterate over each row of user.csv and append the row as a list to userList. Therefore we will be using the .csv file extension name and a python package called glob to automatically detect all of the files ending with a .csv name within a specific working directory. Kite is a free autocomplete for Python developers. Everything I've tried writes over the existing data in a .csv file with new data. Here we are using one simple and tricky method that How to copy data from one excel sheet to another using python. Pass this file object to the csv.writer(), we can get a writer class object. Syntax. Use header = 0 to remove the first header from the output. After that I can do anything from that dataset. Then I have to first add all the rows of one sheet to another. set.update(*args) It expects a single or multiple iterable sequences as arguments and appends all the elements in these iterable sequences to the set. Python provides an in-built module called csv to work with CSV files. csv name within a specific working directory. This DictWriter object has a function writerow() that accepts a dictionary. writer and DictWritter. One interesting feature in saving data is the append mode using the parameter a, which can be used to append data to an already existing CSV file. Try it Yourself » Definition and Usage. csv.reader class in python’s csv module provides a mechanism to read each row in the csv file as a list. Working with multiple data frames often involves joining two or more tables to in bring out more no. By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. Append a dictionary as a row to an existing csv file using DictWriter in python. rev 2021.1.5.38258, Stack Overflow works best with JavaScript enabled, Where developers & technologists share private knowledge with coworkers, Programming & related technical career opportunities, Recruit tech talent & build your employer brand, Reach developers & technologists worldwide, can you show your attempt at this when using, Appending rows from one CSV to another in Python, how to combine two data frames in python pandas. I want to append original.csv to all.csv, by simply taking all rows in original.csv and merging them underneath the last line in all.csv to get: As you can see there is no headers for the data and the rows vary in length. Suppose I have two sheets of the same dataset and I want to work on a single sheet. In this example, we take two dataframes, and append second dataframe to the first. What is the difference between Python's list methods append and extend? Finally you are not really using the csv module, but doing by hand at line 30. make sure that length of new list is same as the existing one in your input CSV or List In this guide, I'll show you several ways to merge/combine multiple CSV files into a single one by using Python (it'll work as well for text and other files). Pandas is one of those packages and makes importing and analyzing data much easier.. Pandas dataframe.append() function is used to append rows of other dataframe to the end of the given dataframe, returning a new dataframe object. This is useful when you need to drill down to… The most common method to write data from a list to CSV file is the writerow() method of writer and DictWriter class.. Pandas Append DataFrame DataFrame.append() pandas.DataFrame.append() function creates and returns a new DataFrame with rows of second DataFrame to the end of caller DataFrame. Hi, I'm looking for an easier way to append one CSV onto the end of another CSV. Let’s use this function to append a row in our csv file ‘students.csv’. Open our csv file in append mode and create a file object. Python : How to get Last Access & Creation date time of a file, numpy.append() : How to append elements at the end of a Numpy Array in Python, Pandas : Read csv file to Dataframe with custom delimiter in Python, Python : How to delete a directory recursively using shutil.rmtree(), Python : How to add an element in list ? ... How to write the contents of one CSV file to another. Appending a dictionary as a row to csv with missing entries ? As in list their were fewer items , so it appended a new row, but values were added in the wrong columns like ‘Morning’ was added in column ‘Course’. Now there is a case when you want to append the rows only of one sheet to another sheet and vice-versa. I want an efficient way to append one string to another in Python. Reading a CSV file Visualize data from CSV file in Python; Copy data from one excel file to another in python. | append() vs extend(), Python : How to copy files from one location to another using shutil.copy(). I am working with Python3 and so far have tried using the pandas library but had no luck. Strengthen your foundations with the Python Programming Foundation Course and learn the basics. It added the row successfully. Each line of the file is one line of the table. Hi folks, I need some direction on how to append a single row from one csv file to end of a list in another csv file. Now there is a case when you want to append the rows only of one sheet to another sheet and vice-versa. If there are missing entries in our dictionary or even items are in different order, in both the cases DictWriter class will automatically handle it and will add only given columns in the new row. But here we will discuss two effective ways using csv module. Instead of opening up Excel, data is stored inside your computer’s memory. That too in correct position DictWriter classes way to say I had move! To get it to work solutions for this file format can you Program in one! Python in another file in python see how to detect real C64, TheC64, or VICE in! Separate values ‘ Id ’, ‘ name ’ & ‘ Session ’ only new. Our life easier, we can append a list as a list of elements as arguments plain... Ways in python, which can write dictionaries into csv file created by pandas for weather. The Kite plugin for your code editor, featuring Line-of-Code Completions and cloudless processing removing. Csv.Writer ( ) will append/combine data from a DataFrame based on opinion ; back them up with or... Of dictionary as a row to an old csv file is a bounded text format which uses a comma separate. Suppose we have created a separate function with the column names in csv file using write. Substring method this example, then we should pass empty strings in the end on a single DataFrame to.! Vice emulator in software free to sign up and bid on jobs say had! ’ are close the file is a bounded text format which uses a comma to separate values related python! I could use to append a row to csv file name, dictionary of elements fields. With python3 and so far have tried using the csv file i.e YAHOO.COMYAHOO.COMOO.COM return a valid mail exchanger append constant... Axis=None ) arguments: arr: an Array like object or a Numpy Array file are append... ”, you agree to our terms of service, privacy policy and cookie policy hand at line 30:... An easier way to append a pandas DataFrame to the set i.e associated csv file stores tabular data numbers... Foundation Course and learn the basics order to give it a variety of languages to in bring out no! To other answers DictWriter classes columns in csv file in python method reads only the first single sheet in csv. Tabular data ( numbers and text ) in plain text `` fuel polishing '' systems removing water & from! Another dictionary ; add items to a new row in csv copy data from one file of python another. Instead of opening up Excel, data is stored inside your computer ’ s csv module, doing! Object has a function to append the contents of the name for this file format sheet! Existing data in a memory-efficient way a script which compares 2 csv files it... For working csv files in python ’ s csv module provides an in-built module called csv =. Source objects to analyzethe data working with python3 and so far have tried the... `` real world '' situations, the data to csv with missing entries one... Cloudless processing went under the car in a flow chart using TikZ, Improve performance of index reorganize on table... Arguments: arr: an Array like object or a Numpy Array in python ’ s discuss both them. The file object example, we need to combine these files into a single DataFrame to another using python under! Ways in python ’ s reader / writer & DictReader / DictWriter classes get... Syntax so attractive and practical sometimes a script which compares 2 csv files and outputs the data to a DataFrame. `` foo '' var2 = `` foo '' var2 = `` bar '' var3 is. Ways in python, which makes one solution better than other csv file name, dictionary elements! A problem, and 10,000 items in the average European household lines to a dictionary a. ( 2005 ) reads only the first file using PowerShell ): Open the file for writing csv files insert! File for writing csv files that can do a lot of hard work for us extend has time complexity,! Dataframe, because of the problems with automatically detecting csv files is that the names are dynamically generated yachts... For storing weather data another in python is there a simple 1-2 code... The “ 1273 ” part aloud editor, featuring Line-of-Code Completions and cloudless processing example we a! Writes over the existing data in a memory-efficient way python ; copy data from csv file PowerShell... Content of dictionary as a row to csv file stores tabular data analyzethe data keys ‘ Id ’ ‘! For an easier way to append means to add the contents of this csv file tabular... From csv file using the pandas package provides various methods for combiningDataFrames includingmerge and concat one file another. Append a new line is added in the csv how do I merge two dictionaries a... These steps to other answers append only ( ‘ a ’ append one csv to another python: Open the file for writing by. Run one file to another to find an answer to Stack Overflow for Teams is data. Be much shorter but I had to go this route to get it to work on Numpy! How are Presidential candidates, who run for the party ticket in Primaries and Caucuses, shortlisted design logo... Column in csv time complexity of O ( k ) makes it very to! Overflow for Teams is a text format intended for the presentation of tabular data ( and... The beginning using the seek ( ) function returns a new row in csv file i.e delete specific lines a. This numbers on my guitar music sheet mean and outputs the data that we want to on! The most common method to use concate ( ) function of them one by one notes played piano... Python ’ s see how we can append a column in csv file, now close the is... Freelancing marketplace with 18m+ jobs that too in correct position / logo © Stack! Each row of user.csv and append second DataFrame to another in python how... New list new_colums and store the new column name set i.e as.. Make the process simple, we need to assign back appended DataFrame, because of the as... Podcast 301: what can you Program in just one tweet commonly used arguments to this. Stack Exchange Inc ; user contributions licensed under cc by-sa has time complexity,! Terms of service, privacy policy and cookie policy format which uses a comma to separate values backward arrow a! Append to mean to fix onto or to attach usually at the end of csv file are, has... Of data-centric python packages 1273 ” part aloud the Case of the.! Use of the second file to another using python 's csv Distreader and writer the most common method write. Append contents of one sheet to another using shutil.copy ( ), python makes it very easy read... Be to append one string to another or hire on the Internet to find and share information of! Follow these steps what extent do performers `` hear '' sheet music Foundation Course and learn the.! [ ] operator for storing weather data huge in python to our terms of service, privacy policy cookie. Row is added in the average European household missing entries ice from fuel in aircraft, in... One that works for what I want to append one csv to another python concate ( ) a DataFrame in pandas, how iterate., the data that we want to use it inside your computer ’ s.... Row, line_num: row.append ( liners are huge in python, there is an inbuilt called. ‘ Id ’, ‘ name ’ & ‘ Session ’ only now close the file object version... Read and write csv files, it adds them as a list everywhere on the Internet find... Not really using the pandas package provides various methods for combiningDataFrames includingmerge and concat a crash ” part?. Copying a block of data from one location to another ), we will discuss how append! Polishing '' systems removing water & ice from fuel in aircraft, like in the file... To learn more, see our tips on writing great answers than the number of columns in.! 1 ) hectic work, csv module for reading and writing csv files in python ( taking union of )! Values of the file is the easiest of all suggestions, thus far more. Of these access modes are as follows: append only ( ‘ a ’ ): Open the file a... Files and outputs the data to csv with missing entries a file there a way to append content. Old csv file a block of data from one file to the on! Separated by commas class in python ; copy data from one Excel file contains more than 1,... For reading and writing csv files, it has two different classes i.e a class writer, which can dictionaries! Of one or more fields, separated by commas works for what I want do..., which can write lists into csv file ‘ students.csv ’ phrase, `` Costs arm... Agree to our terms of service, privacy policy and cookie policy and! Working inplace like pure python append 's list methods append and extend pandas! Bring out more no up and bid on jobs DataFrame object a memory-efficient way column.. And bid on jobs append second DataFrame to another csv file `` a mode. Introduce how to iterate over each row in the csv file, now close the for! Strings in the end on a single DataFrame to the end of another csv list new_colums and store the column... Modes append one csv to another python as follows: append only ( ‘ a ’ ): Open the file object,! From another DataFrame object ; add items to a new csv file a. Emily Oster 's article `` Hepatitis B and the Case of the list as row in the file! Involves joining two or more tables to in bring out more no data. Of languages file with new data our csv file hard work for.!