问题：Python将项目添加到元组
我有一些object.ID-s，我尝试将其作为元组存储在用户会话中。当我添加第一个时，它可以工作，但是元组看起来像，(u'2',)但是当我尝试使用mytuple = mytuple + new.idgot error 添加新的时can only concatenate tuple (not "unicode") to tuple。
I have some object.ID-s which I try to store in the user session as tuple. When I add first one it works but tuple looks like (u'2',) but when I try to add new one using mytuple = mytuple + new.id got error can only concatenate tuple (not "unicode") to tuple.
回答 0
您需要将第二个元素设为1元组，例如：
a = ('2',)
b = 'z'
new = a + (b,)
You need to make the second element a 1-tuple, eg:
a = ('2',)
b = 'z'
new = a + (b,)
回答 1
从Python 3.5（PEP 448）开始，您可以在元组，列表集和字典中进行解包：
a = ('2',)
b = 'z'
new = (*a, b)
Since Python 3.5 (PEP 448) you can do unpacking within a tuple, list set, and dict:
a = ('2',)
b = 'z'
new = (*a, b)
回答 2
从元组到列表再到元组：
a = ('2',)
b = 'b'
l = list(a)
l.append(b)
tuple(l)
或附有较长的项目清单
a = ('2',)
items = ['o', 'k', 'd', 'o']
l = list(a)
for x in items:
l.append(x)
print tuple(l)
给你
>>>
('2', 'o', 'k', 'd', 'o')
这里的重点是：列表是可变的序列类型。因此，您可以通过添加或删除元素来更改给定列表。元组是不可变的序列类型。您不能更改元组。因此，您必须创建一个新的。
From tuple to list to tuple :
a = ('2',)
b = 'b'
l = list(a)
l.append(b)
tuple(l)
Or with a longer list of items to append
a = ('2',)
items = ['o', 'k', 'd', 'o']
l = list(a)
for x in items:
l.append(x)
print tuple(l)
gives you
>>>
('2', 'o', 'k', 'd', 'o')
The point here is: List is a mutable sequence type. So you can change a given list by adding or removing elements. Tuple is an immutable sequence type. You can’t change a tuple. So you have to create a new one.
回答 3
元组只能允许添加tuple到其中。最好的方法是：
mytuple =(u'2',)
mytuple +=(new.id,)
我使用以下数据尝试了相同的情况，但似乎一切正常。
>>> mytuple = (u'2',)
>>> mytuple += ('example text',)
>>> print mytuple
(u'2','example text')
Tuple can only allow adding tuple to it. The best way to do it is:
mytuple =(u'2',)
mytuple +=(new.id,)
I tried the same scenario with the below data it all seems to be working fine.
>>> mytuple = (u'2',)
>>> mytuple += ('example text',)
>>> print mytuple
(u'2','example text')
回答 4
>>> x = (u'2',)
>>> x += u"random string"
Traceback (most recent call last):
File "<pyshell#11>", line 1, in <module>
x += u"random string"
TypeError: can only concatenate tuple (not "unicode") to tuple
>>> x += (u"random string", ) # concatenate a one-tuple instead
>>> x
(u'2', u'random string')
>>> x = (u'2',)
>>> x += u"random string"
Traceback (most recent call last):
File "<pyshell#11>", line 1, in <module>
x += u"random string"
TypeError: can only concatenate tuple (not "unicode") to tuple
>>> x += (u"random string", ) # concatenate a one-tuple instead
>>> x
(u'2', u'random string')
回答 5
＃1表格
a = ('x', 'y')
b = a + ('z',)
print(b)
＃2表格
a = ('x', 'y')
b = a + tuple('b')
print(b)
#1 form
a = ('x', 'y')
b = a + ('z',)
print(b)
#2 form
a = ('x', 'y')
b = a + tuple('b')
print(b)
回答 6
最简单的说，添加到元组的最简单方法是用括号和逗号将要添加的元素括起来。
t = ('a', 4, 'string')
t = t + (5.0,)
print(t)
out: ('a', 4, 'string', 5.0)
Bottom line, the easiest way to append to a tuple is to enclose the element being added with parentheses and a comma.
t = ('a', 4, 'string')
t = t + (5.0,)
print(t)
out: ('a', 4, 'string', 5.0)
