St Louis
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4 min readWhen reading a CSV file with a broken header in pandas, you can use the parameter header=None when calling the pd.read_csv() function. This will read the file without considering the first row as the header.You can then manually specify the column names by using the names parameter and passing a list of column names as an argument.Alternatively, you can read the file without a header and then add the column names using the df.columns attribute.
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5 min readTo select a range of rows in a pandas DataFrame, you can use the slicing operator [] with the range of rows you want to select. For example, if you want to select rows 2 to 5, you can do df[2:6] where df is your DataFrame. The range specified in the slicing operator is exclusive, so it will select rows 2, 3, 4, and 5. You can also use boolean indexing with conditions to select a range of rows based on certain criteria.
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5 min readTo custom sort a datetime column in pandas, you can convert the datetime column to a pandas datetime data type using the pd.to_datetime() function. Once the column is converted to datetime, you can use the sort_values() function to sort the datetime column in either ascending or descending order. Additionally, you can use the sort_index() function to sort the datetime column based on the index of the dataframe.
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3 min readTo extract a substring from a pandas column, you can use the str.extract() method in pandas. This method allows you to specify a regular expression pattern to extract the desired substring from the column. Simply provide the pattern as an argument to str.extract() and assign the result to a new column in the dataframe. This will create a new column with the extracted substring values.
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5 min readTo use groupby with filter in pandas, you can first create a groupby object based on one or more columns in your dataframe. Then, you can apply a filter to this groupby object using the filter() method. The filter() method allows you to specify a function that will be applied to each group, and only the groups for which the function returns True will be included in the filtered result.
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5 min readTo parse a nested JSON with arrays using pandas dataframe, you can first read the JSON file into a pandas DataFrame using the pd.read_json() function. If the JSON contains nested data with arrays, you can use the json_normalize() function to flatten the nested data into a tabular format. This will allow you to access and manipulate the data more easily using pandas functions. Additionally, you can use the pd.concat() function to merge the nested data with the existing DataFrame if needed.
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5 min readTo get the match value in a pandas column, you can use the isin method. This method checks if each value in the column is contained in a list of specified values. For example, you can create a new column that specifies whether each value in the original column matches a certain value by using the syntax df['new_column'] = df['original_column'].isin(['value_to_match']). This will return a boolean series where True indicates a match and False indicates no match.
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5 min readTo calculate the number of days in a specific column in pandas, you can use the pd.to_datetime function to convert the values in that column to datetime objects. Then, you can subtract the minimum value from the maximum value to get the total number of days. For example, if you have a DataFrame df with a column named 'date': import pandas as pd # Convert the 'date' column to datetime objects df['date'] = pd.
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5 min readTo delete rows containing nonsense characters in pandas, you can use the str.contains method with a regular expression to identify rows that contain specific characters or patterns that you consider as nonsense. Once you have identified these rows, you can use the drop method to remove them from your DataFrame. This will help clean your data and remove any unwanted or irrelevant information that may affect your analysis.
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6 min readTo extend date in a pandas dataframe, you can use the pd.to_datetime() function to convert the date column to a datetime object. Then, you can use the timedelta function to add a specific time period to each date in the dataframe. This allows you to extend the dates in the dataframe by a specified number of days, months, etc. Finally, you can update the date column in the dataframe with the extended dates.
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4 min readTo use asyncio with pandas dataframe, you can first create a coroutine function that handles the data processing or manipulation on the dataframe. Then, use the async keyword before the function definition to make it a coroutine function. Next, create an asyncio event loop and use the asyncio.run() function to run the coroutine function within the event loop. This allows you to asynchronously process the data in the pandas dataframe using asyncio.