The StructType and StructFields are used to define a schema or its part for the Dataframe. This defines the name, datatype, and nullable flag for each column. StructType object is the collection of StructFields objects. It is a Built-in datatype that contains the list of StructField.Apply a function to a Dataframe elementwise. Deprecated since version 2.1.0: DataFrame.applymap has been deprecated. Use DataFrame.map instead. This method applies a function that accepts and returns a scalar to every element of a DataFrame. Python function, returns a single value from a single value. If ‘ignore’, propagate NaN values ...pandas.DataFrame.corr# DataFrame. corr (method = 'pearson', min_periods = 1, numeric_only = False) [source] # Compute pairwise correlation of columns, excluding NA ...First, if you have the strings 'TRUE' and 'FALSE', you can convert those to boolean True and False values like this:. df['COL2'] == 'TRUE' That gives you a bool column. You can use astype to convert to int (because bool is an integral type, where True means 1 and False means 0, which is exactly what you want):The Pandas len () function returns the length of a dataframe (go figure!). The safest way to determine the number of rows in a dataframe is to count the length of the dataframe’s index. To return the length of the index, write the following code: >> print ( len (df.index)) 18.Group DataFrame using a mapper or by a Series of columns. A groupby operation involves some combination of splitting the object, applying a function, and combining the results. This can be used to group large amounts of data and compute operations on these groups. Used to determine the groups for the groupby.DataFrame.join(other, on=None, how='left', lsuffix='', rsuffix='', sort=False, validate=None) [source] #. Join columns of another DataFrame. Join columns with other DataFrame either on index or on a key column. Efficiently join multiple DataFrame objects by index at once by passing a list. Index should be similar to one of the columns in this one. DataFrame.corr (col1, col2 [, method]) Calculates the correlation of two columns of a DataFrame as a double value. DataFrame.count () Returns the number of rows in this DataFrame. DataFrame.cov (col1, col2) Calculate the sample covariance for the given columns, specified by their names, as a double value. property DataFrame.loc [source] #. Access a group of rows and columns by label (s) or a boolean array. .loc [] is primarily label based, but may also be used with a boolean array. Allowed inputs are: A single label, e.g. 5 or 'a', (note that 5 is interpreted as a label of the index, and never as an integer position along the index). Set the DataFrame index (row labels) using one or more existing columns or arrays (of the correct length). The index can replace the existing index or expand on it. Parameters. keyslabel or array-like or list of labels/arrays. This parameter can be either a single column key, a single array of the same length as the calling DataFrame, or a list ...Oct 27, 2020 · I need to read an HTML table into a dataframe from a web page. I need to load json-like records into a dataframe without creating a json file. I need to load csv-like records into a dataframe without creating a csv file. I need to merge two dataframes, vertically or horizontally. I have to transform a column of a dataframe into one-hot columns In many situations, a custom attribute attached to a pd.DataFrame object is not necessary. In addition, note that pandas-object attributes may not serialize. So pickling will lose this data. Instead, consider creating a dictionary with appropriately named keys and access the dataframe via dfs['some_label']. df = pd.DataFrame() dfs = {'some ...Jan 31, 2022 · Method 1 — Pivoting. This transformation is essentially taking a longer-format DataFrame and making it broader. Often this is a result of having a unique identifier repeated along multiple rows for each subsequent entry. One method to derive a newly formatted DataFrame is by using DataFrame.pivot. pandas.DataFrame.dtypes #. pandas.DataFrame.dtypes. #. Return the dtypes in the DataFrame. This returns a Series with the data type of each column. The result’s index is the original DataFrame’s columns. Columns with mixed types are stored with the object dtype. See the User Guide for more. For a DataFrame, a column label or Index level on which to calculate the rolling window, rather than the DataFrame’s index. Provided integer column is ignored and excluded from result since an integer index is not used to calculate the rolling window. If 0 or 'index', roll across the rows. If 1 or 'columns', roll across the columns. DataFrame.nunique(axis=0, dropna=True) [source] #. Count number of distinct elements in specified axis. Return Series with number of distinct elements. Can ignore NaN values. Parameters: axis{0 or ‘index’, 1 or ‘columns’}, default 0. The axis to use. 0 or ‘index’ for row-wise, 1 or ‘columns’ for column-wise. dropnabool, default ... pandas.DataFrame.columns# DataFrame. columns # The column labels of the DataFrame. Examples >>> df = pd. Returns a new DataFrame using the row indices in rowIndices. Filter(PrimitiveDataFrameColumn<Int64>) Returns a new DataFrame using the row indices in rowIndices. FromArrowRecordBatch(RecordBatch) Wraps a DataFrame around an Arrow Apache.Arrow.RecordBatch without copying data. GroupBy(String)DataFrame.to_html ([buf, columns, col_space, ...]) Render a DataFrame as an HTML table. DataFrame.to_feather (path, **kwargs) Write a DataFrame to the binary Feather format. DataFrame.to_latex ([buf, columns, header, ...]) Render object to a LaTeX tabular, longtable, or nested table. DataFrame.to_stata (path, *[, convert_dates, ...])Feb 19, 2021 · Python | Pandas dataframe.add () Python is a great language for doing data analysis, primarily because of the fantastic ecosystem of data-centric Python packages. Pandas is one of those packages and makes importing and analyzing data much easier. Dataframe.add () method is used for addition of dataframe and other, element-wise (binary operator ... Group DataFrame using a mapper or by a Series of columns. A groupby operation involves some combination of splitting the object, applying a function, and combining the results. This can be used to group large amounts of data and compute operations on these groups. Used to determine the groups for the groupby.Saving a DataFrame to a Python dictionary dictionary = df.to_dict() Saving a DataFrame to a Python string string = df.to_string() Note: sometimes may be useful for debugging Working with the whole DataFrame Peek at the DataFrame contents df.info() # index & data types n = 4 dfh = df.head(n) # get first n rows DataFrame.mask(cond, other=_NoDefault.no_default, *, inplace=False, axis=None, level=None) [source] #. Replace values where the condition is True. Where cond is False, keep the original value. Where True, replace with corresponding value from other . If cond is callable, it is computed on the Series/DataFrame and should return boolean Series ...pandas.DataFrame.plot. #. Make plots of Series or DataFrame. Uses the backend specified by the option plotting.backend. By default, matplotlib is used. The object for which the method is called. Only used if data is a DataFrame. Allows plotting of one column versus another. Only used if data is a DataFrame.This boolean dataframe is of a similar size as the first original dataframe. The value is True at places where given element exists in the dataframe, otherwise False. Then find the names of columns that contain element 22. We can accomplish this by getting names of columns in the boolean dataframe which contains True.First, if you have the strings 'TRUE' and 'FALSE', you can convert those to boolean True and False values like this:. df['COL2'] == 'TRUE' That gives you a bool column. You can use astype to convert to int (because bool is an integral type, where True means 1 and False means 0, which is exactly what you want):When your DataFrame contains a mixture of data types, DataFrame.values may involve copying data and coercing values to a common dtype, a relatively expensive operation. DataFrame.to_numpy(), being a method, makes it clearer that the returned NumPy array may not be a view on the same data in the DataFrame. Accelerated operations# DataFrame.astype(dtype, copy=None, errors='raise') [source] #. Cast a pandas object to a specified dtype dtype. Parameters: dtypestr, data type, Series or Mapping of column name -> data type. Use a str, numpy.dtype, pandas.ExtensionDtype or Python type to cast entire pandas object to the same type.axis {0 or ‘index’} for Series, {0 or ‘index’, 1 or ‘columns’} for DataFrame. Axis along which to fill missing values. For Series this parameter is unused and defaults to 0. inplace bool, default False. If True, fill in-place. Note: this will modify any other views on this object (e.g., a no-copy slice for a column in a DataFrame).DataFrame.to_numpy(dtype=None, copy=False, na_value=_NoDefault.no_default) [source] #. Convert the DataFrame to a NumPy array. By default, the dtype of the returned array will be the common NumPy dtype of all types in the DataFrame. For example, if the dtypes are float16 and float32, the results dtype will be float32 .pandas.DataFrame.dtypes #. pandas.DataFrame.dtypes. #. Return the dtypes in the DataFrame. This returns a Series with the data type of each column. The result’s index is the original DataFrame’s columns. Columns with mixed types are stored with the object dtype. See the User Guide for more.DataFrame.describe(percentiles=None, include=None, exclude=None) [source] #. Generate descriptive statistics. Descriptive statistics include those that summarize the central tendency, dispersion and shape of a dataset’s distribution, excluding NaN values. Analyzes both numeric and object series, as well as DataFrame column sets of mixed data ...DataFrame.astype(dtype, copy=None, errors='raise') [source] #. Cast a pandas object to a specified dtype dtype. Parameters: dtypestr, data type, Series or Mapping of column name -> data type. Use a str, numpy.dtype, pandas.ExtensionDtype or Python type to cast entire pandas object to the same type.labels for the Series and DataFrame objects. It can only contain hashable objects. A pandas Series has one Index; and a DataFrame has two Indexes. # --- get Index from Series and DataFrame idx = s.index idx = df.columns # the column index idx = df.index # the row index # --- Notesome Index attributes b = idx.is_monotonic_decreasingaxis {0 or ‘index’} for Series, {0 or ‘index’, 1 or ‘columns’} for DataFrame. Axis along which to fill missing values. For Series this parameter is unused and defaults to 0. inplace bool, default False. If True, fill in-place. Note: this will modify any other views on this object (e.g., a no-copy slice for a column in a DataFrame). New in version 1.5.0: Added support for .tar files. May be a dict with key ‘method’ as compression mode and other entries as additional compression options if compression mode is ‘zip’.Let’s discuss how to get column names in Pandas dataframe. First, let’s create a simple dataframe with nba.csv file. Now let’s try to get the columns name from above dataset. Method #3: Using keys () function: It will also give the columns of the dataframe. Method #4: column.values method returns an array of index.pandas.DataFrame.corr# DataFrame. corr (method = 'pearson', min_periods = 1, numeric_only = False) [source] # Compute pairwise correlation of columns, excluding NA ...DataFrame Creation¶ A PySpark DataFrame can be created via pyspark.sql.SparkSession.createDataFrame typically by passing a list of lists, tuples, dictionaries and pyspark.sql.Row s, a pandas DataFrame and an RDD consisting of such a list. pyspark.sql.SparkSession.createDataFrame takes the schema argument to specify the schema of the DataFrame ... DataFrame.corr (col1, col2 [, method]) Calculates the correlation of two columns of a DataFrame as a double value. DataFrame.count () Returns the number of rows in this DataFrame. DataFrame.cov (col1, col2) Calculate the sample covariance for the given columns, specified by their names, as a double value.By default, convert_dtypes will attempt to convert a Series (or each Series in a DataFrame) to dtypes that support pd.NA. By using the options convert_string, convert_integer, convert_boolean and convert_floating, it is possible to turn off individual conversions to StringDtype, the integer extension types, BooleanDtype or floating extension ...First, if you have the strings 'TRUE' and 'FALSE', you can convert those to boolean True and False values like this:. df['COL2'] == 'TRUE' That gives you a bool column. You can use astype to convert to int (because bool is an integral type, where True means 1 and False means 0, which is exactly what you want):DataFrame.mask(cond, other=_NoDefault.no_default, *, inplace=False, axis=None, level=None) [source] #. Replace values where the condition is True. Where cond is False, keep the original value. Where True, replace with corresponding value from other . If cond is callable, it is computed on the Series/DataFrame and should return boolean Series ... Pandas 数据结构 - DataFrame. DataFrame 是一个表格型的数据结构，它含有一组有序的列，每列可以是不同的值类型（数值、字符串、布尔型值）。DataFrame 既有行索引也有列索引，它可以被看做由 Series 组成的字典（共同用一个索引）。 DataFrame 构造方法如下：So you can use the isnull ().sum () function instead. This returns a summary of all missing values for each column: DataFrame.isnull () .sum () 6. Dataframe.info. The info () function is an essential pandas operation. It returns the summary of non-missing values for each column instead: DataFrame.info () 7.Divides the values of a DataFrame with the specified value (s), and floor the values. ge () Returns True for values greater than, or equal to the specified value (s), otherwise False. get () Returns the item of the specified key. groupby () Groups the rows/columns into specified groups.pandas.DataFrame.dtypes #. pandas.DataFrame.dtypes. #. Return the dtypes in the DataFrame. This returns a Series with the data type of each column. The result’s index is the original DataFrame’s columns. Columns with mixed types are stored with the object dtype. See the User Guide for more.When your DataFrame contains a mixture of data types, DataFrame.values may involve copying data and coercing values to a common dtype, a relatively expensive operation. DataFrame.to_numpy(), being a method, makes it clearer that the returned NumPy array may not be a view on the same data in the DataFrame. Accelerated operations#pandas.DataFrame.plot. #. Make plots of Series or DataFrame. Uses the backend specified by the option plotting.backend. By default, matplotlib is used. The object for which the method is called. Only used if data is a DataFrame. Allows plotting of one column versus another. Only used if data is a DataFrame. Jul 12, 2022 · We will first read in our CSV file by running the following line of code: Report_Card = pd.read_csv ("Report_Card.csv") This will provide us with a DataFrame that looks like the following: If we wanted to access a certain column in our DataFrame, for example the Grades column, we could simply use the loc function and specify the name of the ... Jan 11, 2023 · Pandas DataFrame is a 2-dimensional labeled data structure like any table with rows and columns. The size and values of the dataframe are mutable,i.e., can be modified. It is the most commonly used pandas object. Pandas DataFrame can be created in multiple ways. Let’s discuss different ways to create a DataFrame one by one. DataFrame.shape is an attribute (remember tutorial on reading and writing, do not use parentheses for attributes) of a pandas Series and DataFrame containing the number of rows and columns: (nrows, ncolumns). A pandas Series is 1-dimensional and only the number of rows is returned. I’m interested in the age and sex of the Titanic passengers.Pandas DataFrame is a 2-dimensional labeled data structure like any table with rows and columns. The size and values of the dataframe are mutable,i.e., can be modified. It is the most commonly used pandas object. Pandas DataFrame can be created in multiple ways. Let’s discuss different ways to create a DataFrame one by one.sep str, default ‘,’. String of length 1. Field delimiter for the output file. na_rep str, default ‘’. Missing data representation. float_format str, Callable, default None Jul 12, 2022 · We will first read in our CSV file by running the following line of code: Report_Card = pd.read_csv ("Report_Card.csv") This will provide us with a DataFrame that looks like the following: If we wanted to access a certain column in our DataFrame, for example the Grades column, we could simply use the loc function and specify the name of the ... DataFrame.drop(labels=None, *, axis=0, index=None, columns=None, level=None, inplace=False, errors='raise') [source] #. Drop specified labels from rows or columns. Remove rows or columns by specifying label names and corresponding axis, or by directly specifying index or column names. When using a multi-index, labels on different levels can be ...class pandas.DataFrame(data=None, index=None, columns=None, dtype=None, copy=None) [source] #. Two-dimensional, size-mutable, potentially heterogeneous tabular data. Data structure also contains labeled axes (rows and columns). Arithmetic operations align on both row and column labels. Can be thought of as a dict-like container for Series objects.Apply a function to a Dataframe elementwise. Deprecated since version 2.1.0: DataFrame.applymap has been deprecated. Use DataFrame.map instead. This method applies a function that accepts and returns a scalar to every element of a DataFrame. Python function, returns a single value from a single value. If ‘ignore’, propagate NaN values ... DataFrame.astype(dtype, copy=None, errors='raise') [source] #. Cast a pandas object to a specified dtype dtype. Parameters: dtypestr, data type, Series or Mapping of column name -> data type. Use a str, numpy.dtype, pandas.ExtensionDtype or Python type to cast entire pandas object to the same type. The DataFrame is one of these structures. This tutorial covers pandas DataFrames, from basic manipulations to advanced operations, by tackling 11 of the most popular questions so that you understand -and avoid- the doubts of the Pythonistas who have gone before you. For more practice, try the first chapter of this Pandas DataFrames course for free!This is really bad variable naming. What is returned from read_html is a list of dataframes. So, you really should use something like list_of_df = pd.read_html.... Then df = list_of_df[0], to get the first dataframe representing the first table in a webpage. –To read the multi-line JSON as a DataFrame: val spark = SparkSession.builder().getOrCreate() val df = spark.read.json(spark.sparkContext.wholeTextFiles("file.json").values) Reading large files in this manner is not recommended, from the wholeTextFiles docs. Small files are preferred, large file is also allowable, but may cause bad performance.Add a Row to a Pandas DataFrame. The easiest way to add or insert a new row into a Pandas DataFrame is to use the Pandas .concat () function. To learn more about how these functions work, check out my in-depth article here. In this section, you’ll learn three different ways to add a single row to a Pandas DataFrame.Dask DataFrame. A Dask DataFrame is a large parallel DataFrame composed of many smaller pandas DataFrames, split along the index. These pandas DataFrames may live on disk for larger-than-memory computing on a single machine, or on many different machines in a cluster. One Dask DataFrame operation triggers many operations on the constituent ... DataFrame Creation¶ A PySpark DataFrame can be created via pyspark.sql.SparkSession.createDataFrame typically by passing a list of lists, tuples, dictionaries and pyspark.sql.Row s, a pandas DataFrame and an RDD consisting of such a list. pyspark.sql.SparkSession.createDataFrame takes the schema argument to specify the schema of the DataFrame ...DataFrame.mask(cond, other=_NoDefault.no_default, *, inplace=False, axis=None, level=None) [source] #. Replace values where the condition is True. Where cond is False, keep the original value. Where True, replace with corresponding value from other . If cond is callable, it is computed on the Series/DataFrame and should return boolean Series ... pandas.DataFrame.dtypes #. pandas.DataFrame.dtypes. #. Return the dtypes in the DataFrame. This returns a Series with the data type of each column. The result’s index is the original DataFrame’s columns. Columns with mixed types are stored with the object dtype. See the User Guide for more. pandas.DataFrame.at# property DataFrame. at [source] #. Access a single value for a row/column label pair. Similar to loc, in that both provide label-based lookups.Use at if you only need to get or set a single value in a DataFrame or Series.Sep 17, 2018 · Pandas where () method is used to check a data frame for one or more condition and return the result accordingly. By default, The rows not satisfying the condition are filled with NaN value. Syntax: DataFrame.where (cond, other=nan, inplace=False, axis=None, level=None, errors=’raise’, try_cast=False, raise_on_error=None) DataFrame.shape is an attribute (remember tutorial on reading and writing, do not use parentheses for attributes) of a pandas Series and DataFrame containing the number of rows and columns: (nrows, ncolumns). A pandas Series is 1-dimensional and only the number of rows is returned. I’m interested in the age and sex of the Titanic passengers. Column label for index column (s) if desired. If not specified, and header and index are True, then the index names are used. A sequence should be given if the DataFrame uses MultiIndex. Upper left cell row to dump data frame. Upper left cell column to dump data frame. Write engine to use, ‘openpyxl’ or ‘xlsxwriter’.When your DataFrame contains a mixture of data types, DataFrame.values may involve copying data and coercing values to a common dtype, a relatively expensive operation. DataFrame.to_numpy(), being a method, makes it clearer that the returned NumPy array may not be a view on the same data in the DataFrame. Accelerated operations#Pandas DataFrame describe () Pandas describe () is used to view some basic statistical details like percentile, mean, std, etc. of a data frame or a series of numeric values. When this method is applied to a series of strings, it returns a different output which is shown in the examples below.pandas.DataFrame.dtypes #. pandas.DataFrame.dtypes. #. Return the dtypes in the DataFrame. This returns a Series with the data type of each column. The result’s index is the original DataFrame’s columns. Columns with mixed types are stored with the object dtype. See the User Guide for more. 1 Melt: The .melt () function is used to reshape a DataFrame from a wide to a long format. It is useful to get a DataFrame where one or more columns are identifier variables, and the other columns are unpivoted to the row axis leaving only two non-identifier columns named variable and value by default.Pandas 数据结构 - DataFrame. DataFrame 是一个表格型的数据结构，它含有一组有序的列，每列可以是不同的值类型（数值、字符串、布尔型值）。DataFrame 既有行索引也有列索引，它可以被看做由 Series 组成的字典（共同用一个索引）。 DataFrame 构造方法如下：Dealing with Rows and Columns in Pandas DataFrame. A Data frame is a two-dimensional data structure, i.e., data is aligned in a tabular fashion in rows and columns. We can perform basic operations on rows/columns like selecting, deleting, adding, and renaming. In this article, we are using nba.csv file.Feb 20, 2019 · Python | Pandas DataFrame.columns. Pandas DataFrame is a two-dimensional size-mutable, potentially heterogeneous tabular data structure with labeled axes (rows and columns). Arithmetic operations align on both row and column labels. It can be thought of as a dict-like container for Series objects. This is the primary data structure of the Pandas. When it comes to exploring data with Python, DataFrames make analyzing and manipulating data for analysis easy. This article will look at some of the ins and outs when it comes to working with DataFrames. Python is a powerful tool when it comes to working with data.axis {0 or ‘index’} for Series, {0 or ‘index’, 1 or ‘columns’} for DataFrame. Axis along which to fill missing values. For Series this parameter is unused and defaults to 0. inplace bool, default False. If True, fill in-place. Note: this will modify any other views on this object (e.g., a no-copy slice for a column in a DataFrame). Saving a DataFrame to a Python dictionary dictionary = df.to_dict() Saving a DataFrame to a Python string string = df.to_string() Note: sometimes may be useful for debugging Working with the whole DataFrame Peek at the DataFrame contents df.info() # index & data types n = 4 dfh = df.head(n) # get first n rows
Group DataFrame using a mapper or by a Series of columns. A groupby operation involves some combination of splitting the object, applying a function, and combining the results. This can be used to group large amounts of data and compute operations on these groups. Used to determine the groups for the groupby.. Clara belle
Dec 26, 2022 · The StructType and StructFields are used to define a schema or its part for the Dataframe. This defines the name, datatype, and nullable flag for each column. StructType object is the collection of StructFields objects. It is a Built-in datatype that contains the list of StructField. DataFrame.sort_values(by, *, axis=0, ascending=True, inplace=False, kind='quicksort', na_position='last', ignore_index=False, key=None) [source] #. Sort by the values along either axis. Name or list of names to sort by. if axis is 0 or ‘index’ then by may contain index levels and/or column labels. if axis is 1 or ‘columns’ then by may ... DataFrame. insert (loc, column, value, allow_duplicates = _NoDefault.no_default) [source] # Insert column into DataFrame at specified location.DataFrame Creation¶ A PySpark DataFrame can be created via pyspark.sql.SparkSession.createDataFrame typically by passing a list of lists, tuples, dictionaries and pyspark.sql.Row s, a pandas DataFrame and an RDD consisting of such a list. pyspark.sql.SparkSession.createDataFrame takes the schema argument to specify the schema of the DataFrame ... A Data frame is a two-dimensional data structure, i.e., data is aligned in a tabular fashion in rows and columns. Features of DataFrame Potentially columns are of different types Size – Mutable Labeled axes (rows and columns) Can Perform Arithmetic operations on rows and columns StructureDivides the values of a DataFrame with the specified value (s), and floor the values. ge () Returns True for values greater than, or equal to the specified value (s), otherwise False. get () Returns the item of the specified key. groupby () Groups the rows/columns into specified groups.Construct DataFrame from dict of array-like or dicts. Creates DataFrame object from dictionary by columns or by index allowing dtype specification. Of the form {field : array-like} or {field : dict}. The “orientation” of the data. If the keys of the passed dict should be the columns of the resulting DataFrame, pass ‘columns’ (default).Pandas 数据结构 - DataFrame. DataFrame 是一个表格型的数据结构，它含有一组有序的列，每列可以是不同的值类型（数值、字符串、布尔型值）。DataFrame 既有行索引也有列索引，它可以被看做由 Series 组成的字典（共同用一个索引）。 DataFrame 构造方法如下：DataFrame.mask(cond, other=_NoDefault.no_default, *, inplace=False, axis=None, level=None) [source] #. Replace values where the condition is True. Where cond is False, keep the original value. Where True, replace with corresponding value from other . If cond is callable, it is computed on the Series/DataFrame and should return boolean Series ... this is a special case of adding a new column to a pandas dataframe. Here, I am adding a new feature/column based on an existing column data of the dataframe. so, let our dataFrame has columns 'feature_1', 'feature_2', 'probability_score' and we have to add a new_column 'predicted_class' based on data in column 'probability_score'.property DataFrame.loc [source] #. Access a group of rows and columns by label (s) or a boolean array. .loc [] is primarily label based, but may also be used with a boolean array. Allowed inputs are: A single label, e.g. 5 or 'a', (note that 5 is interpreted as a label of the index, and never as an integer position along the index). The DataFrame.index and DataFrame.columns attributes of the DataFrame instance are placed in the query namespace by default, which allows you to treat both the index and columns of the frame as a column in the frame. The identifier index is used for the frame index; you can also use the name of the index to identify it in a query..