Pandas series index. Whether you’re aligning data or just reordering it for aesthetic purposes, understanding how to modify Mar 31, 2022 · This tutorial explains how to get a value from a pandas Series, including several examples. Upvoting indicates when questions and answers are useful. You can bookmark this page Generate a new DataFrame or Series with the index reset. Method 1: Using the index attribute and list comprehension This method involves accessing the index attribute of the Series and using list comprehension to create a list of indices that match the given value. where(cond, other=nan, *, inplace=False, axis=None, level=None) [source] # Replace values where the condition is False. When using a multi-index, labels on different levels can be removed by specifying the level. Jul 11, 2025 · Pandas Series from Dictionary In this article, you will learn about the different methods of configuring the pandas. new_series = pd. copybool, default False Copy input data. For Feb 2, 2015 · In my case I had a pandas Series where the values are tuples of characters: Out[67] 0 (H, H, H, H) 1 (H, H, H, T) 2 (H, H, T, H) 3 (H, H, T, T) 4 (H, T, H, H) Therefore I could use indexing to filter the series, but to create the index I needed apply. iat Access a single value by integer position. Operations between Series (+, -, /, *, **) align values based on their associated index values– they need not be the same length. Remove elements of a Series based on specifying the index labels. Returns: Index pandas. Feb 19, 2024 · This code snippet creates a pandas Series with labeled index and fetches the value at index ‘c’, which is 30. groupby(by=None, axis=0, level=None, as_index=True, sort=True, group_keys=True, observed=<no_default>, dropna=True) [source] # Group Series using a mapper or by a Series of columns. Pandas Series. Jul 11, 2025 · Pandas Series is a one-dimensional labeled array capable of holding data of any type (integer, string, float, python objects, etc. Selecting a row of pandas series/dataframe by integer index Asked 12 years, 3 months ago Modified 4 months ago Viewed 1. MultiIndex / advanced indexing # This section covers indexing with a MultiIndex and other advanced indexing features. Examples To create a Series with a custom index and view the index labels: Operations between Series (+, -, /, *, **) align values based on their associated index values– they need not be the same length. Dec 5, 2022 · Pandas series objects are used to store data when we need to access it using its position as well as labels. array [source] # The ExtensionArray of the data backing this Series or Index. Allowed inputs are: A single label, e. Indexing Data using the [] Operator The [] operator is the basic and frequently used method for indexing in Pandas. May 29, 2020 · You'll need to complete a few actions and gain 15 reputation points before being able to upvote. If no index is specified Pandas automatically assigns default integer indices starting from 0. loc Access a group of rows and columns by label (s). 7 and I want to apply a function which uses the index of the row: def f(x pandas. , I'd Jun 24, 2025 · In pandas, Series. Pandas provide various Series methods and attributes to retrieve the data from Series. drop # Series. In this article, we will discuss different ways to create index in a pandas series. 55 times pandas. Index. If your series index is by datetime, this doesn't work. apply(lambda x: x. May 13, 2015 · I have a pandas series: import pandas as pd s = pd. dtype, or ExtensionDtype, optional Data type for the output Index. This can be used to group large amounts of data and compute Indexing and selecting data # The axis labeling information in pandas objects serves many purposes: Identifies data (i. get_indexer(target, method=None, limit=None, tolerance=None) [source] # Compute indexer and mask for new index given the current index. It’s a straightforward way to iterate over both, which can be particularly useful when the series has a meaningful index. Returns: iterable Iterable of tuples containing the (index, value) pairs from a Series. When drop is True, a Series is returned. ), with each element having an associated label known as its index. I'm using python 2. Feb 19, 2024 · Problem Formulation: While working with Pandas, a versatile data manipulation library in Python, changing the index of a Series can be a common task. This article explores multiple ways to create a Pandas Series with step-by-step explanations and examples Feb 19, 2024 · The input is a Pandas Series and a value to find; the desired output is the index (or indices) at which the value occurs in the Series. See the Indexing and Selecting Data for general indexing documentation. See code examples, explanations, and tips for handling errors and multiple occurrences. iteritems())) The slowest run took 6. The labels need not be unique but must be a hashable type. Aug 20, 2013 · This solution only works if your series has a sequential integer index. reindex() method in pandas is a powerful tool for data manipulation, offering versatility in handling data index changes. You can already get the future behavior and improvements through enabling copy on write pd. However, in some situations, we need to get all labels and values separately. The filter is applied to the labels of the index. values, index=s )) a A b B c C d D e E f F g G h H i I j J dtype: object Timings: In [63]: %timeit pd. In this article, I will explain how to rearrange the index values of a given series in a specific order. DataFrame, pandas. Examples To create a Series with a custom index and view the index labels: pandas. A pandas Series holds labeled data and these labels are called indexes, by using these labels we can access series elements and we can do manipulations on our data. If cond is callable, it is computed on the Series/DataFrame and should return Feb 12, 2018 · pandas. concat(objs, *, axis=0, join='outer', ignore_index=False, keys=None, levels=None, names=None, verify_integrity=False, sort=False, copy=None) [source] # Concatenate pandas objects along a particular axis. 概要 Series の値を取得、設定する方法について解説します。 関連記事 pandas - DataFrame のインデックス操作まとめ - pystyle Series のインデックスを取得する pandas. When freq is not passed, shift the index without realigning the data. Series, which is a 1-D labeled array capable of holding any data. drop(labels=None, *, axis=0, index=None, columns=None, level=None, inplace=False, errors='raise') [source] # Return Series with specified index labels removed. concat # pandas. Seriesの []によるインデックス指定で、行・列および要素を選択し抽出・取得できる。 []に指定する値のタイプによって取得できるデータが異なる。 Index objects # Index # Many of these methods or variants thereof are available on the objects that contain an index (Series/DataFrame) and those should most likely be used before calling these methods directly. This is convenient if you want to create a lazy iterator. g. For Series this parameter is unused and defaults to 0. An element in the series can be accessed similarly to that in an ndarray. Returns: ExtensionArray An ExtensionArray of the values stored within. My condition is "find all tuples which have exactly one 'H'". Mar 27, 2024 · In Series every element contains the corresponding index/index labels, by using these indexes we can get the values from Pandas Series. In this section, we will focus on the final point: namely, how to slice, dice, and generally get and set subsets of pandas objects. 4m times How do I get the index column name in Python's pandas? Here's an example dataframe: Column 1 Index Title Apples 1 Oranges 2 Puppies 3 Duc pandas. Places NA/NaN in locations having no value in the previous index. By the end of this tutorial, creating and manipulating multi-index Series will be second nature to you. The name of a Series becomes its index or column name if it is used to form a DataFrame. where # Series. Series(data[' Nov 23, 2024 · Learn how to access the first element of a Pandas Series without relying on the index. Dec 5, 2024 · Explore various efficient methods to find the index of an element in a Pandas Series. tupleize_colsbool (default: True) When True, attempt to create a MultiIndex if possible. at Access a single value by label. . Practical examples included. 3 4 4 0. 0. Series(dict((v,k) for k,v in s. See also DataFrame. Get practical examples, speed tests, and alternative solutions. Nov 18, 2021 · A pandas Series holds labeled data, by using these labels we can access series elements and we can do manipulations on our data. A new object is produced unless the new index is equivalent to the current one and copy=False. 5 or 'a', (note that 5 is interpreted as a label of the index, and never as an integer position along the index). Jul 11, 2025 · In this article we will understand how to create a Pandas series from lists along with explanations and examples. This is the equivalent of the numpy. iloc[] property is used to access a Series by its integer location (i. Note The copy keyword will change behavior in pandas 3. Lets say I have a MultiIndex Series s: &gt;&gt;&gt; s values a b 1 2 0. , position-based index). loc # property Series. Return a boolean Series showing whether each element in the Series matches an element in the passed sequence of values exactly. Series () command to make a pandas series from a dictionary followed by a few practical tips for using them. 7 to take a numerical column of my dataframe data and make it an individual object (series) with an index of dates that is another column from data. filter # Series. 1 3 6 0. Pandas如何更改Pandas Series的索引值 在本文中，我们将介绍如何更改Pandas Series的索引值。 Pandas是一个非常流行的Python数据分析库，Series是其中一种重要的数据结构。 每个Series都包含一个索引和一组值，我们可以使用索引来访问这些值。 pandas. What's reputation and how do I get it? Instead, you can save this post to reference later. What is a Series? A Pandas Series is like a column in a table. The copy keyword will be removed in a future version of pandas. series_of_tuples[series_of_tuples. In either case, if inplace=True, no value is returned. Jan 4, 2020 · How can I change the index values of a Pandas Series from the regular integer value that they default to, to values within a list that I have? e. It is also used whenever displaying the Series using the interpreter. get_indexer # final Index. Can also add a layer of hierarchical indexing on the concatenation axis, which may be useful if the labels are the same The index of a Series is used to label and identify each element of the underlying data. Jul 11, 2025 · Pandas Series is a one-dimensional labeled array capable of holding any data type (integers, strings, floats, etc. It will help you quickly look up attributes, methods, syntaxes, and popular operations when solving problems related to series. Whether elements in Series are contained in values. Pandas 在Pandas Series中查找元素的索引 在本文中，我们将介绍如何使用Pandas查找元素在Series中的索引。 Pandas是Python数据分析的重要工具，提供强大的数据结构和数据分析方法。 Series是Pandas中的一种基本数据结构，类似于一维数组。 阅读更多：Pandas 教程 1. Returns: label (hashable object) The name of the Series, also the column name if part of a DataFrame. Learn about Python Pandas Series, a powerful data structure for handling one-dimensional data with ease. Series([421, 122, 275, 847, 175]) index_v You can also index find any number occurrence of the value by treating the the above statement as a list: animals[animas == 'mammoth']. index values. reindex(index=None, *, axis=None, method=None, copy=None, level=None, fill_value=None, limit=None, tolerance=None) [source] # Conform Series to new index with optional filling logic. Where False, replace with corresponding value from other. In this article, we will discuss how to rename the index in a pandas series. If you want the index of the minimum, use idxmin. Copy-on-Write will be enabled by default, which means that all methods with a copy keyword will use a lazy copy mechanism to defer the copy and ignore the copy keyword. min(axis=0, skipna=True, numeric_only=False, **kwargs) [source] # Return the minimum of the values over the requested axis. This comes handy when index is need to be MultiIndex is also called Hierarchical Indexing, it is a powerful feature in pandas that allows you to work with higher-dimensional data in lower-dimensional structures like Series (1D) and DataFrame (2D). index attribute is used to retrieve the index labels associated with the given Series object. Example: import A Pandas Series is a one-dimensional labeled array that can hold data of any type. shift(periods=1, freq=None, axis=0, fill_value=<no_default>, suffix=None) [source] # Shift index by desired number of periods with an optional time freq. Using Series () method without index parameter In this case, dictionary keys are taken in a sorted order to construct the Dec 2, 2022 · We use pandas series objects for various data processing tasks in python. Set the DataFrame index (row labels) using one or more existing columns or arrays (of the correct length). If cond is callable, it is computed on the Series/DataFrame and should return Notes For more information on pandas indexing, see the indexing user guide. The index of a DataFrame is a series of labels that identify each row. The index can replace the existing index or expand on it. iloc[] Property The . Series Jul 15, 2025 · Suppose we want to change the order of the index of series, then we have to use the Series. Returns: Series or DataFrame or None When drop is False (the default), a DataFrame is returned. array # property Series. This method is particularly useful Accessors # pandas provides dtype-specific methods under various accessors. e. It allows us to select columns and filter rows based on conditions. iteritems())) print (s1) a A b B c C d D e E f F g G h H i I j J dtype: object Another the fastest: print (pd. For extension types, this is the actual array. items() [source] # Lazily iterate over (index, value) tuples. Parameters: axis{index (0)} Axis for the function to be applied on. With MultiIndex, pandas objects have multiple levels of index labels. Each value in series associated with the index starts 0 to n-1. Syntax: pandas. min # Series. Returns: pandas Changed in version 2. Allows optional set logic along the other axes. Then we can use the index and values attributes of the Series Accessors # pandas provides dtype-specific methods under various accessors. Parameters PythonのPandasにおけるSeriesの使い方を初心者向けに解説した記事です。Seriesの作成方法や、要素の抽出、追加、削除、インデックスの利用方法など、Seriesについてはこれだけを読んでおけば良いよう、徹底的に解説しています。 Jan 17, 2014 · I'm having a bit of a slow moment with selection and indexing in pandas. The indexer should be then used as an input to ndarray. Each of the returned indexes corresponds to the position where the substring is fully contained between [start:end]. Series(s. iat Access a single value for a row/column pair by integer position. values, which may require converting the data to a different form. The index is an immutable ordered set that can be aligned and indexed in pandas. From basic reordering to advanced techniques for dealing with missing data, understanding how to utilize this function effectively can enhance your data analysis and manipulation capabilities pandas. name [source] # Return the name of the Series. The index can be thought of as an immutable ordered set (technically a multi-set, as it may contain duplicate labels), and is used to index and align data in pandas. Import Pandas and create a Series. Series. Parameters The index can be thought of as an immutable ordered set (technically a multi-set, as it may contain duplicate labels), and is used to index and align data in pandas. items # Series. set_index # DataFrame. index用法及代码示例 Python是进行数据分析的一种出色语言，主要是因为以数据为中心的python软件包具有奇妙的生态系统。 Feb 17, 2024 · In summary, this guide covered several methods for getting a list of indexes in a Pandas Series, from simple attribute access to more advanced techniques involving Boolean indexing and Pandas data accessors. The primary focus will be on Series and DataFrame as they have received more development attention in this area. Series (data, index, dtype, copy) Parameters: data takes ndarrys, list, constants. Python Pandas Series. See full list on sparkbyexamples. reindex # Series. How can I get the index of certain element of a Series in python pandas? (first occurrence would suffice) I. Jun 19, 2023 · In this blog, we will delve into the process of identifying the index of an element within a Pandas Series, a task often undertaken by data scientists and software engineers. sort_index(*, axis=0, level=None, ascending=True, inplace=False, kind='quicksort', na_position='last', sort_remaining=True, ignore_index=False, key=None) [source] # Sort Series by index labels. loc[] is primarily label based, but may also be used with a boolean array. 0: Index can hold all numpy numeric dtypes (except float16). ndarray method argmin. Let’s say you have a Series with default integer indices and pandas. One easy way to re-arrange the index would be to reassign the same Series with the order of the indexes changed. Method 2: Using the . Parameters: condbool Series/DataFrame, array-like, or callable Where cond is True, keep the original value. com Apr 12, 2024 · Learn how to use bracket notation, index attribute, where method, argmax method, list method, try/except block, and Index class to find an element's index in a Pandas Series. ndarray. Use a for loop in combination with iteritems() to iterate through the Series. Elements of a series can be accessed in two ways: Accessing Element from Series with Position Accessing Element Using Label (index) In pandas. index # Series. Using Series() Without an Index Argument The simplest way to create a Pandas Series is by passing a list to the Series() method. ). In this tutorial, you will learn about Pandas Series with the help of examples. . The labels can be integers, strings, or any other hashable type. Labels need not be unique but must be a hashable type. set_index(keys, *, drop=True, append=False, inplace=False, verify_integrity=False) [source] # Set the DataFrame index using existing columns. index # The index (row labels) of the DataFrame. The newly created columns will come first in the DataFrame, followed by the original Series values. Parameters: keyslabel or array-like or list of pandas. If freq is passed (in this case, the index must be date or datetime, or it will raise a NotImplementedError), the index will be increased using Oct 20, 2016 · One posible solution is swap keys and values by: s1 = pd. Jul 11, 2025 · A Pandas Series is like a single column of data in a spreadsheet. Series. provides metadata) using known indicators, important for analysis, visualization, and interactive console display. Parameters: itemslist-like Keep labels from axis which are in items. Parameters: axis{0 or ‘index’} Unused Parameters: dataarray-like (1-dimensional) dtypestr, numpy. In this section, we will focus on the final The index can be thought of as an immutable ordered set (technically a multi-set, as it may contain duplicate labels), and is used to index and align data in pandas. Jul 26, 2025 · In this article, we’ll see various ways to index and select data in Pandas which shows us how to access the parts of our dataset. The result index will be the sorted union of the two indexes. array differs from . iloc Access a group of rows and columns by integer position (s). Equivalent to series + other, but with support to substitute a fill_value for missing data in either one of the inputs. groupby # Series. These are separate namespaces within Series that only apply to specific data types. loc [source] # Access a group of rows and columns by label (s) or a boolean array. sort_index # Series. Feb 18, 2024 · In conclusion, the Series. str. If not specified, this will be inferred from data. dtypes for data Feb 17, 2024 · Method #1 – Using iteritems () The iteritems() function yields pairs of index and value. Each value in a Series is associated with an index, which makes data retrieval and manipulation easy. See the user guide for more usages. It is a one-dimensional array that can hold many types of data such as numbers, words or even other Python objects. We will explore practical ways to set or change the index in a pandas Series, starting from a Series with a default integer index, with the aim of setting a new index. DataFrame. nameobject Name to be stored in the index. 1. Explore its features, methods, and practical applications. Returns a new Series sorted by label if inplace argument is False, otherwise updates the original series and returns None. Parameters PythonのPandasにおけるSeriesの使い方を初心者向けに解説した記事です。Seriesの作成方法や、要素の抽出、追加、削除、インデックスの利用方法など、Seriesについてはこれだけを読んでおけば良いよう、徹底的に解説しています。 pandas. For instance, you may have a Series with indices ranging from 0 to n and wish to adjust these to a new set of labels for better data comprehension or to conform with other datasets. The index is used for label-based access and alignment, and can be accessed or modified using this attribute. Designed for both beginners and experienced users, this blog provides detailed explanations and examples to ensure you can leverage the Series index effectively in your data analysis workflows. If you want to get labels and values individually. Enables automatic and explicit data alignment. values # property Series. A groupby operation involves some combination of splitting the object, applying a function, and combining the results. filter(items=None, like=None, regex=None, axis=None) [source] # Subset the dataframe rows or columns according to the specified index labels. Method 1: Using Series. But once NaN values, indexing issues, and in-place modifications come into play, things can get tricky. Parameters: targetIndex Aug 5, 2013 · Pandas allows you to create a DataFrame from a dict with Series as the values and the column names as the keys. This comprehensive guide explores the Pandas Series index in depth, covering its creation, manipulation, properties, and practical applications. reset_index() function generate a new DataFrame or Series with the index reset. It is a one-dimensional array holding data of any type. Previously only int64/uint64/float64 dtypes were accepted. For NumPy native types, this is a thin (no copy) wrapper around numpy. Allows intuitive getting and setting of subsets of the data set. name # property Series. count('H')==1)] I admit it is Mar 10, 2023 · This is a concise and comprehensive cheat sheet that focuses on Series in Pandas. It shows how to use the [] operator with a labeled index to retrieve the requested value from the Series. x = pd. Feb 10, 2019 · Pandas series is a One-dimensional ndarray with axis labels. index By default, the original index and original name is reused. I have a Date Time series from which I am trying to select certain elements, along with their date time index in order to a pandas. shift # Series. index. This is useful when the index needs to be treated as a column, or when the index is meaningless and needs to be reset to the default before another operation. values [source] # Return Series as ndarray or ndarray-like depending on the dtype. mode pandas. Pandas, a widely-used data manipulation library in Python, offers robust data structures and functions designed for efficient handling of tabular and timeseries data. Jun 10, 2025 · To change the index order in a Pandas Series, you can use the reindex() method. pandas. This method returns an iterable tuple (index, value). take to align the current data to the new index. reindex () Method of pandas module for performing this task. index # DataFrame. When it finds a Series as a value, it uses the Series index as part of the DataFrame index. Parameters: labelssingle label or list-like Index pandas. This method allows you to specify the new order of the index labels. at Access a single value for a row/column pair by label. The object supports both integer- and label-based indexing and provides a host of methods for performing operations involving the index. Labels can be called indexes and data present in a series called values. Feb 24, 2024 · In this tutorial, we will focus on creating Multi-Index Series in Pandas, providing you with five practical examples to enhance your data manipulation skills. Learn how to create and modify the index of a pandas Series, which is used to label and identify each element of the data. Aug 20, 2013 · I know this is a very basic question but for some reason I can't find an answer. set_index() A series in Python pandas is a kind of one dimensional array of any datatype. options. index(sub, start=0, end=None) [source] # Return lowest indexes in each string in Series/Index. Notes For more information on pandas index ing, see the indexing user guide. index[1] #retrieves index of second occurrence of value. Series (data = [1,2,3], index = ['A', 'B', 'C']) How can I change the order of the index, so that s becomes B 2 A 1 C 3 I tried s ['B','A Return Addition of series and other, element-wise (binary operator add). likestr Keep labels from axis for Feb 18, 2025 · At first glance, sorting a pandas Series seems straightforward. Note that this routine does not filter a dataframe on its contents. DataFrame. Feb 19, 2024 · Changing the index can be essential for data alignment operations, merging data sets, and improving data retrieval speeds. Feb 17, 2024 · Overview Updating the index of a Pandas Series is a common task which significantly impacts data manipulation and presentation. amjon bdrhx mjybep dcxb xvg nwgw ghaam pzfhwx ttlar qwcqi