python查询数据库中一列数据并存放在一个列表中

Question

问题遇到的现象和发生背景

python连接postgresql查询数据表中某一列数据，想把查询得到的数据存放在一个list中

用代码块功能插入代码，请勿粘贴截图

import glob
import psycopg2 as psy
import os

filepattern = r'E:\study\Python\argo\202206.tar\202206\202206\*_*.dat'
filelist = glob.glob(filepattern)

"""连接库"""
host = 'localhost'
port = 5432
dbname = 'postgres'
user = 'postgres'
password = '123'
conn = psy.connect(host=host, port=port, dbname=dbname, user=user, password=password)

cursor = conn.cursor()

sql = '''
SELECT pressure FROM tempsalt
WHERE platformnumber = %s
'''
cursor.execute(sql, [1901302])

print(cursor)
results=cursor.fetchall()
for items in results:
    pre=items[0]
    print(pre)

运行结果及报错内容

4.5
7.1
10.5
15.4
19.6
24.6
30.4
34.3
39.8
44.9
49.8
54.6
59.6
64.6
69.4
74.6
80.5
85.2
89.9
93.6
97.8
110.3
118.5
130.6
140.1
149.9
160.5
170.2
180.4
190.4
200.5
209.8
220.3
229.5
240.5
250.4
260.0
269.9
280.3
290.2
300.2
310.1
319.9
330.0
339.9
349.9
359.9
380.5
400.1
420.2
439.9
459.8
479.7
500.3
549.7
599.9
648.3
700.5
800.0
900.5
999.2
1099.6
1200.3
1298.0
1399.8
1497.4
1599.9
1700.5
1800.4
1900.3

进程已结束,退出代码0

我想要达到的结果

想达到这样的效果：[4.5,7.1,10.5,15.4,19.6,24.6,30.4,34.3,39.8]

Answer 1

这个简单，代码如下，有帮助的话采纳一下哦！

import glob
import psycopg2 as psy
import os

filepattern = r'E:\study\Python\argo\202206.tar\202206\202206\*_*.dat'
filelist = glob.glob(filepattern)

"""连接库"""
host = 'localhost'
port = 5432
dbname = 'postgres'
user = 'postgres'
password = '123'
conn = psy.connect(host=host, port=port, dbname=dbname, user=user, password=password)

cursor = conn.cursor()

sql = '''
SELECT pressure FROM tempsalt
WHERE platformnumber = %s
'''
cursor.execute(sql, [1901302])

print(cursor)
results = cursor.fetchall()
new_results = []
for items in results:
    new_results.append(items[0])

print(new_results)

Answer 2

定义一个list=[]在for循环上面，然后在for循环下面加上list.append(pre)就行了

Answer 3

import glob
import psycopg2 as psy
import os
 
filepattern = r'E:\study\Python\argo\202206.tar\202206\202206\*_*.dat'
filelist = glob.glob(filepattern)
 
"""连接库"""
host = 'localhost'
port = 5432
dbname = 'postgres'
user = 'postgres'
password = '123'
conn = psy.connect(host=host, port=port, dbname=dbname, user=user, password=password)
 
cursor = conn.cursor()
 
sql = '''
SELECT pressure FROM tempsalt
WHERE platformnumber = %s
'''
cursor.execute(sql, [1901302])
 
print(cursor)
pressure_list = []
results=cursor.fetchall()
for items in results:
    pressure_list.append(items[0])
print(pressure_list )
 

Answer 4

定义一个list = []，然后，在循环中用list.append(items[0])