This article mainly introduces you to the pandas in Python. Dataframe to exclude specific lines of the method, the text gives a detailed example code, I believe that everyone's understanding and learning has a certain reference value, the need for friends to see together below. When you use Python for data analysis, one of the most frequently used structures is the dataframe of pandas, about
Python traversal pandas data method summary, python traversal pandas
Preface
Pandas is a python data analysis package that provides a large number of functions and methods for fast and convenient data processing. Pandas defines two data types: Series and DataFrame, which makes data operations easier. Series is a one-di
Pandas basics, pandas
Pandas is a data analysis package built based on Numpy that contains more advanced data structures and tools.
Similar to Numpy, the core is ndarray, and pandas is centered around the two core data structures of Series and DataFrame. Series and DataFrame correspond to one-dimensional sequences and
Teach you how to use Pandas pivot tables to process data (with learning materials) and pandas learning materials
Source: bole online-PyPer
Total2203 words,Read5Minutes.This article mainly explains pandas's pivot_table function and teaches you how to use it for data analysis.
Introduction
Most people may have experience using pivot tables in Excel. In fact, Pandas
[Data analysis tool] Pandas function introduction (I), data analysis pandas
If you are using Pandas (Python Data Analysis Library), the following will certainly help you.
First, we will introduce some simple concepts.
DataFrame: row and column data, similar to sheet in Excel or a relational database table
Series: Single Column data
Axis: 0: Row, 1: Column
Pandas Quick Start (3) and pandas Quick Start
This section mainly introduces the Pandas data structure, this article cited URL: https://www.dataquest.io/mission/146/pandas-internals-series
The data used in this article comes from: https://github.com/fivethirtyeight/data/tree/master/fandango
This data mainly describes
[Data cleansing]-clean "dirty" data in Pandas (3) and clean pandasPreview Data
This time, we use Artworks.csv, And we select 100 rows of data to complete this content. Procedure:
DataFrame is the built-in data display structure of Pandas, and the display speed is very fast. With DataFrame, we can quickly preview and analyze data. The Code is as follows:
import pandas
Pandas data analysis (data structure) and pandas Data Analysis
This article mainly expands pandas data structures in the following two directions: Series and DataFrame (corresponding to one-dimensional arrays and two-dimensional arrays in Series and numpy)
1. First, we will introduce how to create a Series.
1) A sequence can be created using an array.
For example
Data analysis and presentation-Pandas data feature analysis and data analysis pandasSequence of Pandas data feature analysis data
The basic statistics (including sorting), distribution/accumulative statistics, and data features (correlation, periodicity, etc.) can be obtained through summarization (lossy process of extracting data features), data mining (Knowledge formation ).
The. sort_index () method so
, how to do? For more information please go to other blogs, where more detailed instructions are available .Pandas import time data for format conversion Draw multiple graphs on one canvas and add legends1 fromMatplotlib.font_managerImportfontproperties2Font = fontproperties (fname=r"C:\windows\fonts\STKAITI. TTF", size=14)3colors = ["Red","Green"]#the color used to specify the line4Labels = ["Jingdong","12306"]#used to specify the legend5Plt.plot (
The previous Pandas array (Pandas Series)-(3) Vectorization, said that when the two Pandas series were vectorized, if a key index was only in one of the series , the result of the calculation is nan , so what is the way to deal with nan ?1. Dropna () method:This method discards all values that are the result of NaN , which is equivalent to calculating only the va
Sometimes you need to do some work on the values in the Pandas series , but without the built-in functions, you can write a function yourself, using the Pandas series 's apply method, You can call this function on each value inside, and then return a new SeriesImport= PD. Series ([1, 2, 3, 4, 5])def add_one (x): return x + 1print s.apply ( Add_one)# results:0 6dtype:int64A chestnut:Names =PD. Serie
Data conversionDelete duplicate elements The duplicated () function of the Dataframe object can be used to detect duplicate rows and return a series object with the Boolean type. Each element pairsshould be a row, if the row repeats with other rows (that is, the row is not the first occurrence), the element is true, and if it is not repeated with the preceding, the metaThe vegetarian is false.A Series object that returns an element as a Boolean is of great use and is particularly useful for fil
-dateutil>=2->pandas)
3, of course, you can also go to Pandas's website download package
HTTPS://PYPI.PYTHON.ORG/PYPI/PANDAS/0.17.1/#downloads
Verifying Pandas
With so many deployments in front, let's see if we can perform a simple pandas code validation.
Because pandas
The pandas Series is much more powerful than the numpy array , in many waysFirst, the pandas Series has some methods, such as:The describe method can give some analysis data of Series :Import= PD. Series ([1,2,3,4]) d = s.describe ()Print (d)Count 4.000000mean 2.500000std 1.290994min 1.00000025% 1.75000050% 2.50000075% 3.250000max 4.000000dtype:float64Second, the bigges
This article describes how the pandas series with the index index is vectorized:1. Index indexed arrays are the same:S1 = PD. Series ([1, 2, 3, 4], index=['a','b','C','D']) S2= PD. Series ([ten, +, +], index=['a','b','C','D'])PrintS1 +s2a11b22C33D44Dtype:int64Add the values corresponding to each index directly2. Index indexed array values are the same, in different order:S1 = PD. Series ([1, 2, 3, 4], index=['a','b','C','D']) S2= PD. Series ([ten, +,
col_namesIf C.endswith ("(g)"):Gram_columns.append (c)GRAM_DF = food_info[gram_columns] The column name at the end of the #把以 "G" is indexed to the Dataframe object, resulting in the corresponding multi-column data.Print (Gram_df.head (3))7) data types in Pandas#object-for String values#int-for integer values#float-for Float values#datetime-for Time values#bool-for Boolean values#print (Food_info.dtypes)3,
datetime index and a tagged column by passing the NumPy array:To view Dataframe's head and tail data:Display indexes, columns, and underlying numpy data:Quick Statistical summary showing the data:Sort by value:Select a single column to produce a series:Select rows through slices by [] selection:4.2.1 Dataframe read/write CSV fileSave Dataframe data to CSV file:Here to save to the C drive, you can view the contents of the file:To read data from a CSV
It's been a lot of red boxes all afternoon.
Python2 and Python3 version conflicts
Pip version IssuePip-v
Updatesudo apt-get update
sudo apt-get install Python-dev
Finally do not know how to install, feeling is one of the following two ways‘‘‘ C++ sudo easy_install -U setuptools ‘‘‘ ‘‘‘ C++ sudo pip install --upgrade setuptools ‘‘‘
(Just beginning to try also not, do not know why suddenly magic can.) If not again, run both sides, see there is an answer is to run on both
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