--- title:【Pandas】Pandas的兩種資料類型 --- # 【Pandas】Pandas的兩種資料類型 [TOC] :::warning :notebook_with_decorative_cover: **學習目標**:Series and DataFrame。 ::: :::warning :calendar: **學習日程** 學習耗費時間:2021.06.13 筆記製作時間:2021.06.13 ::: Import numpy as np Import pandas as pd ## Series Series is a one-dimensional labeled array capable of holding any data type (integers, strings, floating point numbers, Python objects, etc.). The axis labels are collectively referred to as the index. s = pd.Series(data, index=index) Series格式就是一個一維陣列的資料,在這裡我們宣告一個pandas的Series類型資料,非常簡單的使用.Series()並將數值放到一個變數中。 Index可以不一定是要從0開始也可以是其他的內容 ```python= s=pd.Series(np.random(5),index:["a","b","c","d","e"]) pd.Series(5,index=["a","b","c"]) ``` 前面所提到的最基本的一個Series格式,其實之前提到的dictionary也可以變成Series。 ```python= d={"b":1,"a":0,"c",2} ``` ## DataFrame DataFrame is a 2-dimensional labeled data structure with columns of potentially different types. You can think of it like a spreadsheet or SQL table, or a dict of Series objects. It is generally the most commonly used pandas object. df=pd.Datarame() ```python= d = { "one": pd.Series([1.0, 2.0, 3.0], index=["a", "b", "c"]), "two": pd.Series([1.0, 2.0, 3.0, 4.0], index=["a", "b", "c", "d"]) } df = pd.DataFrame(d) df ``` | |one| two | | -------- | -------- | -------- | | a | 1.0 | 1.0 | | b | 2.0 | 2.0 | | c | 3.0 | 3.0 | | d | NaN | 4.0 | **分析** --- ```python df.index ``` Index(['a', 'b', 'c', 'd'], dtype='object') ```python= df['one'] #抓整行出來 ``` | |one| | -------- | -------- | -------- | | a | 1.0 | 1.0 | | b | 2.0 | 2.0 | | c | 3.0 | 3.0 | | d | NaN | 4.0 | ```python= df["three"] = df["one"] * df["two"] #新稱新的欄位 ``` | |one| two |three| | -------- | -------- | -------- | -------- | | a | 1.0 | 1.0 | 1.0| | b | 2.0 | 2.0 | 4.0 | | c | 3.0 | 3.0 | 9.0| | d | NaN | 4.0 | NaN | ```python= df["flag"] = df["one"] > 2 ``` | |one| two |three|flag| | -------- | -------- | -------- | -------- |-------- | | a | 1.0 | 1.0 | 1.0| False| | b | 2.0 | 2.0 | 4.0 | False| | c | 3.0 | 3.0 | 9.0| True | d | NaN | 4.0 | NaN | False ```python= del df["two"] #刪除欄位 ``` | |one| three| flag| | -------- | -------- | -------- |-------- | | a | 1.0 | 1.0 |False| | b | 2.0 | 4.0 |False| | c | 3.0 | 9.0 |True | d | NaN | NaN |False|
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