[英]Counting sort and list comprehension in Python
I have problem with understand how to resolve error in my code. 我在了解如何解决代码中的错误时遇到问题。 Here it comes: 它来了:
def counting_sort(some_list, max=100000):
licznik = [0] * (max+1)
for x in some_list:
licznik[x] = licznik[x]+1
i=0
for x in range(max+1):
for y in range(licznik[x]):
some_list[i]=x
i=i+1
return some_list.reverse()
def gen(number, b=100000):
some_list = []
return [some_list.append(random.randint(0, b)) for x in xrange(number)]
domain = [10000, 25000, 50000, 100000, 200000, 300000, 400000, 500000, 750000, 1000000]
for element in domain:
print 'Results for: ' + str(element) + ' elements:'
for j in range(0, 10):
temp_list = gen(element)
start = time.time()
counting_sort(temp_list)
end = time.time() - start
print end
This is problem with line: 这是行的问题:
for x in some_list:
licznik[x] = licznik[x]+1
I guess that it should be resolved by list comprehension, but I have no idea how to transform it this way. 我想应该通过列表理解来解决它,但是我不知道如何以这种方式进行转换。 Any helping advice? 有帮助的建议吗? Thanks for advance. 感谢前进。
You are filling some_list
with None
values in your function gen
. 您正在使用gen
函数中的None
值填充some_list
。 Change the line 换线
return [some_list.append(random.randint(0, b)) for x in xrange(number)]
to: 至:
return [(random.randint(0, b)) for x in xrange(number)]
Your gen
function is wrong... list.append
returns None
and modifies somelist
in place, change to: 您的gen
函数是错误的... list.append
返回None
并在适当位置修改somelist
,更改为:
def gen(number, b=100000):
return [random.randint(0, b) for x in xrange(number)]
To demonstrate: 展示:
some_list = []
print [some_list.append(10) for _ in xrange(5)]
# [None, None, None, None, None]
print some_list
# [10, 10, 10, 10, 10]
And you're returning the list of None
s. 您将返回None
的列表。
You are trying to use a None
value as a key to the list licznik
on line 5. 您试图将None
值用作第5行上的licznik
列表的键。
If you modify your Gen
function to this, it should work. 如果您将Gen
函数修改为此,它将起作用。
def gen(number, b=100000):
return [(random.randint(0, b)) for x in xrange(number)]
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