用多个条件过滤 Pandas DataFrame
Suraj Joshi
2023年1月30日
本教程解释了如何基于多个条件从 DataFrame 中过滤元素。
我们将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)
输出：
Stock Price Sector
0 Tesla 835 Technology
1 Moderna Inc 112 Health Technology
2 Facebook 267 Technology
3 Boeing 209 Aircraft
根据多个条件使用索引过滤 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)
输出：
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
它过滤了 stocks_df 中的所有元素，其中 Sector 列的值是 Technology，Price 列的值小于 500。
我们在 [] 内指定条件，用&或|运算符连接条件，根据多个条件对数值进行索引。&运算符代表逻辑和，意思是这两个条件必须为真才能选择一个元素。|运算符代表逻辑或，意思是如果满足任何条件就可以选择一个元素。
使用 query() 方法基于多个条件过滤 DataFrame 的元素
我们将由&或|运算符连接的多个条件作为参数传递给 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)
输出：
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
作者： Suraj Joshi
Suraj Joshi is a backend software engineer at Matrice.ai.
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