pandas查詢筆記
阿新 • • 發佈:2020-09-09
1、將下面字典建立為DataFrame
data = {"grammer":["Python","C","Java","GO",np.nan,"SQL","PHP","Python"],
"score":[1,2,np.nan,4,5,6,7,10]}
df = pd.DataFrame(data)
2、提取含有字串Python的行
df[df['grammer'] == 'Python']
3、輸出df的所有列名
df.columns
4、修改第二列列名為'popularity'
df.rename(columns={'score':'popularity'},inplace = True)
# inplace:是否原地替換。布林值,預設為False。如果為True,則在原DataFrame上進行操作,返回值為None。
5、統計grammer列中每種程式語言出現的次數
df['grammer'].value_counts()
6、將空值用上下值的平均值填充
df['popularity'] = df['popularity'].fillna(df['popularity'].interpolate()) #fillna(method引數控制向上還是向下填充,ffill:向下自動填充,bfill:向上自動填充)
7、提取popularity列中值大於3的行
df[df['popularity'] > 3]
8、按照grammer列進行去除重複值
df.drop_duplicates(['grammer'])
9、計算popularity列平均值
df['popularity'].mean()
10、將grammer列轉換為list
df['grammer'].to_list()
11、將DataFrame儲存為EXCEL
df.to_excel('test.xlsx')
12、檢視資料行列數
df.shape
13、提取popularity列值大於3小於7的行
df[(df['popularity'] > 3) & (df['popularity'] < 7)]
14、交換兩列位置
temp = df['popularity']
df.drop(labels=['popularity'],axis=1,inplace=True)
df.insert(0,'popularity',temp)
15、提取popularity列最大值所在行
df[df['popularity'] == df['popularity'].max()]