在 Python 中打印集合时删除集合标识符
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Removing set identifier when printing sets in Python
提问by johns4ta
I am trying to print out the contents of a set and when I do, I get the set identifier in the print output. For example, this is my output set(['a', 'c', 'b', 'e', 'd', 'f', 'gg', 'ff', 'jk'])" for the code below. I want to get rid of the word set. My code is very simple and is below.
我试图打印出一个集合的内容，当我这样做时，我在打印输出中得到了集合标识符。例如，这是我的输出set(['a', 'c', 'b', 'e', 'd', 'f', 'gg', 'ff', 'jk'])“对于下面的代码。我想摆脱这个词set。我的代码很简单，在下面。
infile = open("P3TestData.txt", "r")
words = set(infile.read().split())
print words
Here is my output again for easy reference: set(['a', 'c', 'b', 'e', 'd', 'f', 'gg', 'ff', 'jk'])
这是我的输出，以供参考： set(['a', 'c', 'b', 'e', 'd', 'f', 'gg', 'ff', 'jk'])
采纳答案by Martijn Pieters
You could convert the set to a list, just for printing:
您可以将集合转换为列表，仅用于打印：
print list(words)
or you could use str.join()to join the contents of the set with a comma:
或者您可以使用str.join()逗号连接集合的内容：
print ', '.join(words)
回答by slezica
The printstatement uses set's implementation of __str__(). You can:
该print语句使用set的实现__str__()。你可以：
Roll out your own printing function, instead of using
print. A simple way to get a nicer formatting may be to uselist's implementation of__str__()instead:print list(my_set)Override the
__str__()implementation in your ownsetsubclass.
推出您自己的打印功能，而不是使用
print. 获得更好格式的一种简单方法可能是使用list的实现__str__()：print list(my_set)覆盖
__str__()您自己的set子类中的实现。
回答by dawg
You can do this if you want the curly braces:
如果你想要花括号，你可以这样做：
>>> s={1,2,3}
>>> s
set([1, 2, 3])
>>> print list(s).__str__().replace('[','{').replace(']','}')
{1, 2, 3}
Or, use format:
或者，使用格式：
>>> print '{{{}}}'.format(', '.join(str(e) for e in set([1,'2',3.0])))
{3.0, 1, 2}
回答by aaaantoine
If printing a set of numbers in Python 3, you can alternatively use slicing.
如果在 Python 3 中打印一组数字，您也可以使用切片。
Python 3.3.5
>>> s = {1, 2, 3, 4}
>>> s
{1, 2, 3, 4}
>>> str(s)[1:-1]
'1, 2, 3, 4'
This doesn't translate well when porting back to Python2...
移植回 Python2 时，这不能很好地转换...
Python 2.7.6
>>> s = {1, 2, 3, 4}
>>> str(s)[1:-1]
'et([1, 2, 3, 4]'
>>> str(s)[5:-2]
'1, 2, 3, 4'
On the other hand, to join()integer values you have to convert to string first:
另一方面，对于join()整数值，您必须先转换为字符串：
Python 2.7.6
>>> strings = {'a', 'b', 'c'}
>>> ', '.join(strings)
'a, c, b'
>>> numbers = {1, 2, 3, 4}
>>> ', '.join(numbers)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: sequence item 0: expected string, int found
>>> ', '.join(str(number) for number in numbers)
'1, 2, 3, 4'
This is still more correct than slicing, however.
然而，这仍然比切片更正确。
回答by cs01
This subclass works for numbers and characters:
这个子类适用于数字和字符：
class sset(set):
def __str__(self):
return ', '.join([str(i) for i in self])
print set([1,2,3])
print sset([1,2,3])
outputs
产出
set([1, 2, 3])
1, 2, 3
