PSQL & Python = 如何返回 "elements" 的列表

Question

我有这个代码：

cur.execute("SELECT numbers FROM table")
supp = cur.fetchall()
for item in supp:
    print item

并打印：

('one',)
('two',)
('three',)

我怎样才能拥有？

one
two
three

Answer 1

每个item对应查询结果的一行，每一行由一个元组表示。如果你想得到每个元组的第一项，你可以 unpack them in the for loop:

for value, in supp:
    print(value)

或者，您也可以通过索引 获取第一项：

for row in supp:
    print(row[0])

您也可以将它们放入列表中 list comprehension:

values = [value for value, in supp]

---

演示：

>>> supp = [('one',), ('two', ), ('three', )]
>>> for value, in supp:
...     print(value)
... 
one
two
three
>>> [value for value, in supp]
['one', 'two', 'three']

Answer 2

try:
    supp = cur.fetchall()
    for item in supp:
        print ' | '.join(item)
    return "values printed"
except:
    return "Something went wrong!"