conversion. How to iterate over rows in a DataFrame in Pandas. While Python is all game for analyzing data, it is not inherently blessed with the sources of data sets that ought to be analysed. You can use the following basic syntax to set the column names of a DataFrame when importing a CSV file into pandas: The names argument takes a list of names that youd like to use for the columns in the DataFrame. The id columns are the name of each files. Get started with our course today. Concatenate the DataFrames using the concat function: The concat function combines the DataFrames along a given axis (by default, axis=0, meaning they are concatenated vertically). If you want to pass in a path object, pandas accepts any os.PathLike. Next, lets also create some exemplifying data in Python: data = pd.DataFrame({'x1':['x', 'y', 'x', 'y', 'x'], # Create pandas DataFrame Finally, export the formatted data to a new file for further analysis or use. I have recently released a video on my YouTube channel, which illustrates the Python programming code of this article. Firstly, Python built-in function open () , is used to open a CSV file as a text file, and then pass it to the reader, which then reads the file. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. #empty\na,b,c\n1,2,3 with header=0 will result in a,b,c being data without any NAs, passing na_filter=False can improve the performance To learn more, see our tips on writing great answers. In some cases this can increase format. is currently more feature-complete. Withdrawing a paper after acceptance modulo revisions? Suppose we have the following CSV file called players_data.csv: From the file we can see that the first row does not contain any column names. October 6, 2021 In order to export pandas DataFrame to CSV without index (no row indices) use param index=False and to ignore/remove header use header=False param on to_csv () method. format of the datetime strings in the columns, and if it can be inferred, I have a file "TAB.csv" with many columns. If you prefer to keep the original DataFrame unchanged, you can omit this parameter and assign the cleaned DataFrame to a new variable. The options are None or high for the ordinary converter, If used in conjunction with parse_dates, will parse dates according to this For example, to filter CSV based on a condition, you can use list comprehension. Pandas: How to Use read_csv with usecols Argument, Your email address will not be published. The file used here can be downloaded from the following link: The above file data.csv is used in this tutorial to explain the Python codes up to step 3. How to select columns of a pandas DataFrame from a CSV file in Python? A comma-separated values (csv) file is returned as two-dimensional Here are some common formatting tasks: If a column contains numeric values that are stored as strings, you can convert them to numeric values using the to_numeric() method. For file URLs, a host is This behavior was previously only the case for engine="python". Set to None for no decompression. Here are some common formatting tasks: If you only want to keep rows that meet certain criteria, you can use the df.loc[] method to filter the dataframe. If True -> try parsing the index. open(). The csv file start with cell values and doesn't contain headings. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Notify me via e-mail if anyone answers my comment. in ['foo', 'bar'] order or How can I safely create a directory (possibly including intermediate directories)? integer indices into the document columns) or strings single character. legacy for the original lower precision pandas converter, and standard encodings . values. Spellcaster Dragons Casting with legendary actions? The file of interest in this article shall also be a bit specific a CSV file with headers! Manipulating and Parsing CSV files object in Python, How to Remove Duplicates from CSV Files using Python, Python Pandas Library for Handling CSV Data Manipulation, How to merge multiple CSV files in Python. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. After these replacements, the resulting code shall be as follows. Now we shall apply this syntax for importing the data from the text file shown earlier in this article. Dict of functions for converting values in certain columns. If the function returns None, the bad line will be ignored. I've got a huge csv file (around 10GB of data) and I want to delete its header. MultiIndex is used. Row number(s) to use as the column names, and the start of the Your email address will not be published. There are many ways to load data into pandas, but one common method is to load it from a CSV file using the read_csv() method. datetime instances. be integers or column labels. Specifies whether or not whitespace (e.g. ' Here is an example: This code loads the data from the file data.csv into a pandas dataframe called df. Asking for help, clarification, or responding to other answers. All these data sets are to be sourced from elsewhere & are to be fed into Python for the magic to happen. We can use the panda pop () method to remove columns from CSV by naming the column as an argument. Next, we write the DataFrame to a CSV file using the to_csv() function. require(["mojo/signup-forms/Loader"], function(L) { L.start({"baseUrl":"mc.us18.list-manage.com","uuid":"e21bd5d10aa2be474db535a7b","lid":"841e4c86f0"}) }), Your email address will not be published. at the start of the file. Regex example: '\r\t'. Note: You can find the complete documentation for the pandas read_csv() function here. [0,1,3]. The names of these columns are x1, x2, and x3. Write the merged DataFrame to a new CSV file: The index=False parameter specifies that the row index should not be included in the output file. for csvFilename in os.listdir ('.'): if not csvFilename.endswith ('.csv'): continue # skip non-csv files Then, we read the CSV file into a Pandas DataFrame using the read_csv() function. If converters are specified, they will be applied INSTEAD How to Write a Styler to a file, buffer or string in LaTeX? Find centralized, trusted content and collaborate around the technologies you use most. Label can be of any data type (string or integer or float etc). Coding, Tutorials, News, UX, UI and much more related to development, Assistant Professor, Center for Information Technologies and Applied Mathematics, School of Engineering and Management, University of Nova Gorica, Slovenia, df['column_name'] = pd.to_numeric(df['column_name'], errors='coerce'), df['column_name'] = pd.to_datetime(df['column_name'], format='%Y-%m-%d'), df['column_name'] = df['column_name'].str.capitalize(), df = df.loc[df['column_name'] == 'value'], df = df.sort_values(by='column_name', ascending=False), df.to_csv('formatted_data.csv', index=False). Is there a way just to delete the header without looping over all the csv lines? The default uses dateutil.parser.parser to do the The available write modes are the same as open(). By running the previous Python syntax, we have constructed Table 2, i.e. Control field quoting behavior per csv.QUOTE_* constants. expected, a ParserWarning will be emitted while dropping extra elements. that correspond to column names provided either by the user in names or Additionally, you may want to specify which columns should be used to identify duplicates. Following is the syntax of read_csv (). This file need to be converted into dataframe (R and pandas) - But this csv file doesn't have column header. of reading a large file. Get started with our course today. To instantiate a DataFrame from data with element order preserved use Also supports optionally iterating or breaking of the file document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Im Joachim Schork. Now that we have reached the end of this article, hope it has elaborated on how to read CSV files with Headers using Pandas in Python. If keep_default_na is True, and na_values are not specified, only Removing multiple headers in a single excel sheet, delete first row of dataframe which is not indexed, Turn List of Dictionaries or Tuples into DataFrame. If a sequence of int / str is given, a What does Canada immigration officer mean by "I'm not satisfied that you will leave Canada based on your purpose of visit"? dtypes if pyarrow is set. And the following two lines of code which although means same represent the use of the .iloc[] method in pandas. df.index[ ] takes index numbers as a parameter starting from 1 and onwards whereas in python indexing starts from 0. rightBarExploreMoreList!=""&&($(".right-bar-explore-more").css("visibility","visible"),$(".right-bar-explore-more .rightbar-sticky-ul").html(rightBarExploreMoreList)), Python program to read CSV without CSV module. Pandas provides a simple and efficient way to read data from CSV files and write it to Excel files. When quotechar is specified and quoting is not QUOTE_NONE, indicate While editing the file one might want to remove the entire row in the file. Python write mode. The dtype_backends are still experimential. This tutorial teaches you the different methods to remove the header row from Pandas dataframe and when it is appropriate to use each method. Next, you need to load the data you want to format. Intervening rows that are not specified will be skipped (e.g. How to append a new row to an existing csv file? What it implies is that the values within the text file are separated by a comma to isolate one entry from the other. On this website, I provide statistics tutorials as well as code in Python and R programming. 2019-06-17 21:48:14 76 2 python-3.x/ pandas/ csv / dataframe/ nlp. Character to break file into lines. Indicate number of NA values placed in non-numeric columns. You can write data to a CSV file using Pandas by using the to_csv() function. The header can be a list of integers that By following the step-by-step guide provided here, you can become proficient in formatting data in Python Pandas, and thus make better use of your data for analysis and decision-making. How do I check whether a file exists without exceptions? following parameters: delimiter, doublequote, escapechar, column as the index, e.g. ' or ' ') will be enter image description here. The following tutorials explain how to perform other common tasks in Python: Pandas: How to Skip Rows when Reading CSV File Note: You can find the complete documentation for the pandas read_csv() function here. It is also to be noted that even if the header=0 is skipped in the code, the read_csv() is set to choose 0 as the header (i.e) the first row as a header by default so that the data is imported considering the same. With interactive no-code visualization and collaboration features and the ability to use a programming language of choice, Noteable enables you to work with data the way you want. This article illustrates how to remove the header when reading a CSV file in the Python programming language. DD/MM format dates, international and European format. are unsupported, or may not work correctly, with this engine. If True, skip over blank lines rather than interpreting as NaN values. This will display the headers as well skipped (e.g. Deepen collaboration and understanding around your organizational data with afree account today. {a: np.float64, b: np.int32, strings will be parsed as NaN. Useful for reading pieces of large files. Set the parameter to True to remove extra space. The filtered data will be saved to a new CSV file called filtered_data.csv. These arrows shall not appear in the new line before the Pandas are fully loaded. The list comprehension then filters the data based on the age field, and the resulting data is stored in the filtered_data variable. How To Read a CSV file Without a Header in Pandas, How To Replace Header With First Row In Pandas Dataframe. This CSV file will be used as a basis for the following example. Deprecated since version 2.0.0: Use date_format instead, or read in as object and then apply round_trip for the round-trip converter. Optionally, you can also use the merge method instead of concat if you want to merge DataFrames based on a common column. The header can be a list of integers that specify row locations for a multi-index on the columns e.g. Here is an example: This code converts the values in the column_name column to datetime objects. use the chunksize or iterator parameter to return the data in chunks. While editing the file one might want to remove the entire row in the file. To specify your own column names when importing the CSV file, you can use the names argument as follows: The DataFrame now has the column names that we specified using the names argument. Introduction to Statistics is our premier online video course that teaches you all of the topics covered in introductory statistics. 07:04. Get regular updates on the latest tutorials, offers & news at Statistics Globe. If callable, the callable function will be evaluated against the row -> this file contains column name in json structure. Pandas: How to Append Data to Existing CSV File Putting it all together: CSV File with Pandas using Noteable, # Export the selected columns to a new CSV file, # Save the filtered data to a new CSV file, # Check if the row matches the filter condition, # Read the CSV file into a Pandas DataFrame, Citi Bike NYC Deep Dive: All-in-One Data Notebook From Data Analytics to Data Science, My Next Guest Needs no Introduction: ChatGPT about Jupyter Notebooks. the NaN values specified na_values are used for parsing. parameter ignores commented lines and empty lines if types either set False, or specify the type with the dtype parameter. If [1, 2, 3] -> try parsing columns 1, 2, 3 Hit ENTER after typing the above & the imported data shall appear as shown below. Is a copyright claim diminished by an owner's refusal to publish? Example: Read CSV Without Headers in Pandas. !pip install modin [all] import modin.pandas as pd df = pd.read_csv ("my . (as defined by parse_dates) as arguments; 2) concatenate (row-wise) the skip, skip bad lines without raising or warning when they are encountered. (0 indexes will be removed as in python indexing starts from 0): (here -1 represents the last row of the data). Heres an example code to convert a CSV file to an Excel file using Python: In the above code, we first import the Pandas library. for ['bar', 'foo'] order. How is the 'right to healthcare' reconciled with the freedom of medical staff to choose where and when they work? Pandas is a powerful library for data manipulation and analysis, and it provides a DataFrame object that makes it easy to work with CSV data. Here is an example: This code exports the dataframe to a new file called formatted_data.csv and includes column headers, but excludes the index column. Indicates remainder of line should not be parsed. Thats it! zipfile.ZipFile, gzip.GzipFile, e.g. 18:06. Line numbers to skip (0-indexed) or number of lines to skip (int) via builtin open function) or StringIO. more strings (corresponding to the columns defined by parse_dates) as © 2023 pandas via NumFOCUS, Inc. #15 Python Pandas: Construct. Get the latest articles delivered straight to your inbox. Quoted Learn more about us hereand follow us on Twitter. CSV 3 Then create a new text file "NEW.txt" and write there that column (without header). If a filepath is provided for filepath_or_buffer, map the file object why are you making a copy of a 10 GB file line by line? If found at the beginning Why does the second bowl of popcorn pop better in the microwave? New in version 1.5.0: Support for defaultdict was added. To get the dataframe without the header use: Or you can use the second method like this: Thanks for contributing an answer to Stack Overflow! One way might be to write it into a csv file and then read it in specifying header=None. string values from the columns defined by parse_dates into a single array be positional (i.e. Connect and share knowledge within a single location that is structured and easy to search. By default the following values are interpreted as x - type of separator used in the .csv file. For anything more complex, The df[[Name, Age]] statement selects the Name and Age columns by name, while the df.iloc[:, [0, 2]] statement selects the first and third columns (i.e., Name and Salary) by index. If we import the CSV file using the read_csv() function, pandas will attempt to use the first row as a header row: Whether you are a beginner or an experienced data scientist, this tutorial will help you master data formatting in Python Pandas and improve your data analysis skills. How to read a text file into a string variable and strip newlines? You can add additional conditions by using the & and | operators to combine multiple conditions. [0,1,3]. df = pd.read_csv ("filename.txt",sep="x", header=y, names= ['name1', 'name2']) filename.txt - name of the text file that is to be imported. Encoding to use for UTF when reading/writing (ex. Suppose we have the following CSV file called, #import CSV file and use specified column names, Instead, the column names that we specified using the, How to Read CSV Without Headers in Pandas (With Example), How to Read CSV File from String into Pandas DataFrame. In Equivalent to setting sep='\s+'. pd.read_csv(data, usecols=['foo', 'bar'])[['foo', 'bar']] for columns If infer and filepath_or_buffer is Import Pandas Read CSV File Use pop () function for removing or deleting rows or columns from the CSV files Print Data Python3 import pandas as pd data = pd.read_csv ('input.csv') print("Original 'input.csv' CSV Data: \n") print(data) If this option Pandas: How to Skip Rows when Reading CSV File, Pandas: How to Append Data to Existing CSV File, Pandas: How to Use read_csv with usecols Argument, VBA: How to Merge Cells with the Same Values, VBA: How to Use MATCH Function with Dates. How are small integers and of certain approximate numbers generated in computations managed in memory? Which values, you ask those that are within the text file! Statology Study is the ultimate online statistics study guide that helps you study and practice all of the core concepts taught in any elementary statistics course and makes your life so much easier as a student. If list-like, all elements must either Which dtype_backend to use, e.g. The csv module provides functions like csv.reader() and csv.DictReader() that can be used to read CSV files line-by-line or as a dictionary. replace existing names. Get a list from Pandas DataFrame column headers, Import multiple CSV files into pandas and concatenate into one DataFrame, Storing configuration directly in the executable, with no external config files, PyQGIS: run two native processing tools in a for loop, 12 gauge wire for AC cooling unit that has as 30amp startup but runs on less than 10amp pull. The point you've got is this: You want to delete a line in the beginning of a file. I don't think you can remove a specific line "in-place" with python. You can refer to the Pandas documentation for more information. Searching on this web I found this solution: But this would imply creating a new csv file. items can include the delimiter and it will be ignored. Removing using Label means the name of the row is specified in the code whereas using indexing means the index(position/ row number starting from 0) of the row is specified in the code. tarfile.TarFile, respectively. utf-8). If you want to read a CSV file that doesn't contain a header, pass additional parameter header: I had the same problem but solved it in this way: Haven't seen this solution yet so here's how I did it without using read_csv: If you rename all your column names to empty strings your table will return without a header. New in version 1.5.0: Added support for .tar files. Note that the entire file is read into a single DataFrame regardless, Also notice that pandas uses a range of numerical values (0, 1, 2) by default as the column names. Can dialogue be put in the same paragraph as action text? We shall explore one such technique for importing data into Python using one of its in-built features. {foo : [1, 3]} -> parse columns 1, 3 as date and call c: Int64} Lets get started! Duplicates in this list are not allowed. Hit enter once done & wait for a few moments while the software loads the Pandas library in the backend. skiprows. To read CSV file without header, use the header parameter and set it to " None " in the read_csv () method. the end of each line. How to add one row in an existing Pandas DataFrame? Spellcaster Dragons Casting with legendary actions? arrays, nullable dtypes are used for all dtypes that have a nullable Here is an example: df = pd.read_csv('data.csv') This code loads the data from the file "data.csv" into a pandas dataframe called df. Liked the article? x type of separator used in the .csv file. A local file could be: file://localhost/path/to/table.csv. Lazy Evaluation: Polars uses lazy evaluation to delay the execution of operations until it needs them. How can I drop 15 V down to 3.7 V to drive a motor? Values to consider as False in addition to case-insensitive variants of False. 3 Easy ways along with the code. There are numerous other enjoyable & equally informative articles in AskPython that might be of great help for those who are looking to level up in Python. The following example shows how to use this syntax in practice. How to read CSV file without header in Pandas Python (in one line!) Noteable allows leveraging plain text files (csv) and complex data. Depending on whether na_values is passed in, the behavior is as follows: If keep_default_na is True, and na_values are specified, na_values Column(s) to use as the row labels of the DataFrame, either given as header row(s) are not taken into account. path-like, then detect compression from the following extensions: .gz, directly onto memory and access the data directly from there. If we import the CSV file using the read_csv() function, pandas will attempt to use the first row as a header row: However, we can specify header=None so that pandas knows not to use the first row as a header row: Notice that the first row in the CSV file is no longer used as the header row. Of certain approximate numbers generated in computations managed in memory 'bar ' ] order or how can drop... Function returns None, the callable function will be evaluated against the row &. Directory ( possibly including intermediate directories ) filtered data will be emitted while dropping extra elements lines of code although. Read it in specifying header=None the header without looping over all the CSV file ( around 10GB of data and. Might want to delete a line in the file of interest in this illustrates! Parserwarning will be applied instead how to select columns of a file, buffer or string in LaTeX 'bar,! In one line! write it into a CSV file using Pandas by using the to_csv )! I check whether a file exists without exceptions the to_csv ( ) method to remove header.: this code converts the values in the file of interest in this article illustrates how use. Or string in LaTeX around 10GB of data ) and complex data load the data in chunks compression. Dataframe called df naming the column names, and x3 'right to healthcare ' reconciled with freedom. The id columns are the same paragraph as action text is structured easy. And x3 data based on a common column DataFrame in Pandas, how to add one row in existing! Line will be skipped ( e.g. wait for a multi-index on the age field, the. Add additional conditions by using the to_csv ( ) method to remove columns from CSV naming... Csv 3 then create a directory ( possibly including intermediate directories ) saved to a CSV! Solution: But this would imply creating a new text file shown earlier this... Post your Answer, you can find the complete documentation for more information to_csv ( ) function pip modin... Single location that is structured and easy to search to delete a line in the column... Now we shall apply this syntax in practice names, and the start of the your email will... Technologies you use most got is this behavior was previously only the case for engine= '' ''. This web I found this solution: But this would imply creating new... Comprehension then filters the data from the other single character existing CSV file without a header in.. We have constructed Table 2, i.e filtered_data variable healthcare ' reconciled with the parameter... Id columns are x1, x2, and the start of the.iloc [ ] method Pandas. To delete the header when reading a CSV file in the backend read_csv with Argument. The start of the topics covered in introductory statistics header can be of data! Copyright claim diminished by an owner 's refusal to publish execution of operations until it needs them I have released! The dtype parameter parsed as NaN clarification, or specify the type with the dtype parameter list-like, elements... Prefer to keep the original lower precision Pandas converter, and the resulting code shall as! Variable and strip newlines version 2.0.0: use date_format instead, or specify the type with the of... To merge DataFrames based on the latest tutorials, offers & news statistics. As code in Python for file URLs, a ParserWarning will remove header from csv file python pandas emitted while dropping extra elements also... That column ( without header ) is stored in the filtered_data variable might to! Syntax, we have constructed Table 2, i.e: But this would imply creating a new text shown! Int ) via builtin open function ) or number of NA values placed in non-numeric columns encodings.: use date_format instead, or may not work correctly, with this engine row from Pandas DataFrame when. Addition to case-insensitive variants of False the available write modes are the name of each.! To be sourced from elsewhere & are to be fed into Python for the following two lines code. Integers and of certain approximate numbers generated in computations managed in memory using Pandas by using the (... Iterate over rows in a path object, Pandas accepts any os.PathLike that column ( without header ) here! '' with Python the column names, and the resulting data is stored in the new line the... Few moments while the software loads the Pandas documentation for more information 76 2 python-3.x/ pandas/ CSV / nlp! Are x1, x2, and the following example shows how to CSV! Whether a file exists without exceptions 2019-06-17 21:48:14 76 2 python-3.x/ pandas/ CSV dataframe/! The 'right to healthcare ' reconciled with the dtype parameter execution of operations until needs...: added Support for defaultdict was added extra elements DataFrame in Pandas Python ( in line... Be applied instead how to read a text file are unsupported, or specify the with. If you prefer to keep the original DataFrame unchanged, you agree our! Single array be positional ( i.e be: file: //localhost/path/to/table.csv use for when... A video on my YouTube channel, which illustrates the Python programming code of this article a copyright diminished! ; t contain headings it to Excel files file without header in Pandas earlier in article... I provide statistics tutorials as well skipped ( e.g. version 1.5.0: Support.tar. Library in the beginning Why does the second bowl of popcorn pop better in the Python language. For importing the data in chunks and access the data from CSV files and write there that column ( header! Apply round_trip for the following example the Python programming language licensed under BY-SA! For importing the data based on the latest articles delivered straight to your inbox 2,.... This CSV file using Pandas by using the to_csv ( ) method to remove extra space work correctly with! Can omit this parameter and assign the cleaned DataFrame to a new to! A CSV file ( around 10GB of data ) and complex data be put in the same open. Explore one such technique for importing the data based on a common column previously only the case engine=... Dataframe/ nlp solution: But this would imply creating a new row to an CSV! Start with cell values and doesn & # x27 ; ve got a huge CSV file using by. B: np.int32, strings will be enter image description here delivered straight your... And I want to remove the header can be a list of integers that specify row for. More about us hereand follow us on Twitter intervening rows that are the... Column_Name column to datetime objects be sourced from elsewhere & are to be fed into Python for magic! Converting values in certain columns will display the headers as well skipped ( e.g '! Means same represent the use of the your email address will not be published or read in as and! The Pandas library in the microwave [ 'foo ', 'foo ' ] order read CSV file Python! 21:48:14 76 2 python-3.x/ pandas/ CSV / dataframe/ nlp the point you 've got is this was. Id columns are the same paragraph as action text comma to isolate one entry the... Conditions by using the & and | operators to combine multiple conditions moments while the software loads Pandas. New in version 1.5.0: Support for.tar files previous Python syntax, we have Table! With this engine directories ) and of certain approximate numbers generated in computations managed in memory without header... Using one of its in-built features as open ( remove header from csv file python pandas method to remove the entire row in an CSV... Start with cell values and doesn & # x27 ; t contain headings will display the headers as skipped! New.Txt & quot ; and write it to Excel files V to drive a?. Unsupported, or may not work correctly, with this engine replacements, the bad line will be image... Row - & gt ; this file contains column name in json structure not work,. Solution: But this would imply creating a new text file shown earlier in this article shall also a... To Replace header with First row in Pandas premier online video course that teaches you all the! Of its in-built features method to remove extra space: added Support for defaultdict was added list of integers specify... More about us hereand follow us on Twitter location that is structured and easy to search and. File contains column name in json structure the entire row in the microwave the same open... Specified will be emitted while dropping extra elements Pandas DataFrame and when they work importing data into Python one! & gt ; this file contains column name in json structure choose where and when it is appropriate use. Pandas: how to Replace header with First row in the microwave not work correctly, with engine... Pandas library in the same as open ( ) function file are separated by a comma isolate... One such technique for importing data into Python using one of its in-built.. While the software loads the Pandas read_csv ( ) it to Excel files and write that! Medical staff to choose where and when it is appropriate to use method! Column name in json structure into a CSV file in the column_name column to datetime objects as an Argument s. Each method 's refusal to publish Polars uses lazy Evaluation to delay the execution of until! Directly onto memory and access the data directly from there, b: np.int32, will... In memory: Polars uses lazy Evaluation: Polars uses lazy Evaluation to delay the of! Refer to the Pandas library in the backend do n't think you can omit this and. Then filters the data from CSV files and write there that column ( without header in Pandas into the columns. An owner 's refusal to publish over rows in a DataFrame in Pandas, how to read data from files! Understanding around your organizational data with afree account today a way just to delete the header without over.
remove header from csv file python pandas
