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排序,默认从小到大排
#By default, pandas will sort the data by the column we specify in ascending order and return a new DataFrame # Sorts the DataFrame in-place, rather than returning a new DataFrame. #print food_info["Sodium_(mg)"] food_info.sort_values("Sodium_(mg)", inplace=True) print (food_info["Sodium_(mg)"]) #Sorts by descending order, rather than ascending. food_info.sort_values("Sodium_(mg)", inplace=True, ascending=False) print (food_info["Sodium_(mg)"])
运行结果:
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打开一个csv文件
import pandas as pd import numpy as np titanic_survival = pd.read_csv("titanic_train.csv") titanic_survival.head()
运行结果:
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计算空值个数
#The Pandas library uses NaN, which stands for "not a number", to indicate a missing value. #we can use the pandas.isnull() function which takes a pandas series and returns a series of True and False values age = titanic_survival["Age"] # print(age.loc[0:10]) age_is_null = pd.isnull(age) # print (age_is_null) age_null_true = age[age_is_null] # print (age_null_true) age_null_count = len(age_null_true) print(age_null_count)
运行结果:
pandas数据预处理实例
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转载自blog.csdn.net/weixin_42260102/article/details/103413681
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