用多個條件過濾 Pandas DataFrame

Suraj Joshi 2023年1月30日 2021年1月22日
  1. 根據多個條件使用索引過濾 DataFrame 的元素
  2. 使用 query() 方法基於多個條件過濾 DataFrame 的元素
用多個條件過濾 Pandas DataFrame

本教程解釋瞭如何基於多個條件從 DataFrame 中過濾元素。

我們將在本文中使用下面的 DataFrame。

import pandas as pd

stocks_df = pd.DataFrame({
    'Stock': ["Tesla","Moderna Inc","Facebook","Boeing"],
    'Price': [835,112,267,209],
    'Sector':["Technology","Health Technology","Technology","Aircraft"]
})

print(stocks_df)

輸出:

         Stock  Price             Sector
0        Tesla    835         Technology
1  Moderna Inc    112  Health Technology
2     Facebook    267         Technology
3       Boeing    209           Aircraft

根據多個條件使用索引過濾 DataFrame 的元素

import pandas as pd

stocks_df = pd.DataFrame({
    'Stock': ["Tesla","Moderna Inc","Facebook","Boeing"],
    'Price': [835,112,267,209],
    'Sector':["Technology","Health Technology","Technology","Aircraft"]
})

print("Stocks DataFrame:")
print(stocks_df,"\n")

reqd_stocks = stocks_df[(stocks_df.Sector == "Technology") & (stocks_df.Price <500)]

print("The stocks of technology sector with price less than 500 are:")
print(reqd_stocks)

輸出:

Stocks DataFrame:
         Stock  Price             Sector
0        Tesla    835         Technology
1  Moderna Inc    112  Health Technology
2     Facebook    267         Technology
3       Boeing    209           Aircraft

The stocks of technology sector with price less than 500 are:
      Stock  Price      Sector
2  Facebook    267  Technology

它過濾了 stocks_df 中的所有元素,其中 Sector 列的值是 TechnologyPrice 列的值小於 500。

我們在 [] 內指定條件,用&|運算子連線條件,根據多個條件對數值進行索引。&運算子代表邏輯,意思是這兩個條件必須為真才能選擇一個元素。|運算子代表邏輯,意思是如果滿足任何條件就可以選擇一個元素。

使用 query() 方法基於多個條件過濾 DataFrame 的元素

我們將由&|運算子連線的多個條件作為引數傳遞給 query() 方法。

import pandas as pd

stocks_df = pd.DataFrame({
    'Stock': ["Tesla","Moderna Inc","Facebook","Boeing"],
    'Price': [835,112,267,209],
    'Sector':["Technology","Health Technology","Technology","Aircraft"]
})
print("Stocks DataFrame:")
print(stocks_df,"\n")

reqd_stocks = stocks_df.query("Sector == 'Technology' & Price <500")

print("The stocks of technology sector with price less than 500 are:")
print(reqd_stocks)

輸出:

Stocks DataFrame:
         Stock Price             Sector
0        Tesla    835         Technology
1 Moderna Inc    112 Health Technology
2     Facebook    267         Technology
3       Boeing    209           Aircraft

The stocks of technology sector with price less than 500 are:
      Stock Price      Sector
2 Facebook    267 Technology
Author: Suraj Joshi
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Suraj Joshi is a backend software engineer at Matrice.ai.

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