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Thread: help on understanding this output
Post: help on understanding this output
| >>> flist = []
>>> for i in range(3):
... flist.append(lambda: i)
...
>>> [f() for f in flist] # what will this print out?Why is the above output [2,2,2]?
Thanks,
L |
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landlord1984 |
General Coding Help |
1 |
2,956 |
Mar-08-2017, 08:05 PM |
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Thread: What does 1 do in X = np.array(df.drop(['label'], 1))?
Post: RE: What does 1 do in X = np.array(df.drop(['label...
| (Feb-04-2017, 01:19 PM)buran Wrote: Actually, that is argument fo df.drop http://pandas.pydata.org/pandas-docs/sta....drop.html
Arha....I need to take a rest. My eye seems not working. |
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landlord1984 |
Data Science |
2 |
10,348 |
Feb-04-2017, 03:13 PM |
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Thread: What does 1 do in X = np.array(df.drop(['label'], 1))?
Post: What does 1 do in X = np.array(df.drop(['label'], ...
| X = np.array(df.drop(['label'], 1))I understand this code is to convert a Pandas's dataframe into a numpy array without a column labelled as "label".
But what is 1 doing here?
Accoding to numpy arra... |
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landlord1984 |
Data Science |
2 |
10,348 |
Feb-04-2017, 01:15 PM |
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Thread: Why list(dict.keys()) does not work?
Post: RE: Why list(dict.keys()) does not work?
| (Feb-02-2017, 07:55 AM)wavic Wrote: my_dict = {'a':'aaa','b':'bbb','c':'ccc'}
l = list(my_dict.keys())
print(l)
print(my_dict.keys())
Weird....The script code works. But those in console still d... |
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landlord1984 |
General Coding Help |
5 |
13,657 |
Feb-02-2017, 10:53 AM |
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Thread: Why list(dict.keys()) does not work?
Post: Why list(dict.keys()) does not work?
| dict={'a':'aaa','b':'bbb','c':'ccc'}
list(dict.keys())Quote:TypeError Traceback (most recent call last)
<ipython-input-60-be97bb392967> in <module>()
----&... |
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landlord1984 |
General Coding Help |
5 |
13,657 |
Feb-02-2017, 07:19 AM |
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Thread: Feel hard to learn the topic about " Parsing"
Post: RE: Feel hard to learn the topic about " Parsing"
| (Jan-31-2017, 12:54 PM)Ofnuts Wrote: (Jan-31-2017, 11:51 AM)landlord1984 Wrote: So far I quite enjoyed learning Python from list and class to numpy and pandas. I have practiced ~80 algorithm type ... |
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landlord1984 |
Web Scraping & Web Development |
7 |
6,377 |
Feb-01-2017, 05:46 AM |
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Thread: Feel hard to learn the topic about " Parsing"
Post: Feel hard to learn the topic about " Parsing"
| So far I quite enjoyed learning Python from list and class to numpy and pandas. I have practiced ~80 algorithm type questions from leetcode and Hackrancker. They are nice web source for practice codin... |
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landlord1984 |
Web Scraping & Web Development |
7 |
6,377 |
Jan-31-2017, 11:51 AM |
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Thread: Creating 2D array without Numpy
Post: RE: Creating 2D array without Numpy
| (Jan-27-2017, 09:43 AM)ichabod801 Wrote: The first way doesn't work because [[0] * n] creates a mutable list of zeros once. Then when the second *n copies the list, it copies references to first lis... |
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landlord1984 |
Data Science |
3 |
35,895 |
Jan-27-2017, 05:29 PM |
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Thread: Creating 2D array without Numpy
Post: Creating 2D array without Numpy
| I want to create a 2D array and assign one particular element.
The second way below works.
But the first way doesn't.
I am curious to know why the first way does not work.
Is there any way to create a... |
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landlord1984 |
Data Science |
3 |
35,895 |
Jan-27-2017, 08:57 AM |
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Thread: Where is the loophole in my code
Post: RE: Where is the loophole in my code
| Thanks for the suggestions on efficiency matters. I will spend some time focusing on efficiency stuff.
I realized there are better ways to do this. I just curious about what is wrong by this stupid wa... |
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landlord1984 |
Homework |
15 |
10,129 |
Jan-27-2017, 12:49 AM |
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Thread: map function
Post: RE: map function
| (Jan-27-2017, 12:39 AM)micseydel Wrote: Ok, it sounds like you're using Python 3. Generators are lazy, so until you do something with them they represent more potential than work done. map() and com... |
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landlord1984 |
General Coding Help |
5 |
4,670 |
Jan-27-2017, 12:46 AM |
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Thread: Where is the loophole in my code
Post: RE: Where is the loophole in my code
| What do you mean homework from OP?
I am not a student. I am learning Python by myself. I am practicing by coding those questions from online challenges.
This is a question from Leetcode.
My codes pas... |
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landlord1984 |
Homework |
15 |
10,129 |
Jan-27-2017, 12:29 AM |
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Thread: map function
Post: RE: map function
| (Jan-26-2017, 11:55 PM)micseydel Wrote: map(print,[1,2,3])Output is <map at 0x1099dc160>
I know the map function returns a generator, but shouldn't it execute the function print? |
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landlord1984 |
General Coding Help |
5 |
4,670 |
Jan-27-2017, 12:24 AM |
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Thread: map function
Post: map function
| map(print,[1,2,3])I thought above code should print individual element, but it does not work.
Why map function does not work here?
L |
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landlord1984 |
General Coding Help |
5 |
4,670 |
Jan-26-2017, 11:44 PM |
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Thread: Access 2D array problem
Post: Access 2D array problem
| I got:
SortedArray2D= [['a', 'b', 'c', 'd', 'e'], ['f', 'g', 'h', 'i', 'j'], ['k', 'l', 'm', 'n', 'o'], ['p', 'q', 'r', 's', 't'], ['u', 'v', 'w', 'x', 'y']]print(SortedArray2D[:][1])gives
Quote:['f'... |
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landlord1984 |
Data Science |
1 |
3,330 |
Jan-23-2017, 07:57 AM |
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Thread: Where is the loophole in my code
Post: Where is the loophole in my code
| Question is:
Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements.
For example, given nums = [0, 1, 0, 3, 12], after c... |
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landlord1984 |
Homework |
15 |
10,129 |
Jan-22-2017, 04:05 AM |
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Thread: what is [o,]?
Post: RE: what is [o,]?
| (Jan-21-2017, 09:15 PM)ichabod801 Wrote: Note that brackets [] define a list, and parentheses () define a tuple. A comma is not needed for a one item list, [o] works fine. But a comma is needed for ... |
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landlord1984 |
General Coding Help |
6 |
5,515 |
Jan-22-2017, 03:01 AM |
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Thread: what is [o,]?
Post: RE: what is [o,]?
| (Jan-21-2017, 08:48 AM)landlord1984 Wrote: I am studying following teaching me about composition of class objects. What is o doing here? def print_all_2(self): def gen(o): lA... |
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landlord1984 |
General Coding Help |
6 |
5,515 |
Jan-21-2017, 07:03 PM |
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Thread: what is [o,]?
Post: what is [o,]?
| I am studying following teaching me about composition of class objects. What is o doing here?
def print_all_2(self):
def gen(o):
lAll = [o,]from following codes:
class Node(ob... |
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landlord1984 |
General Coding Help |
6 |
5,515 |
Jan-21-2017, 08:48 AM |
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Thread: Why Python's standard library is hard to read?
Post: Why Python's standard library is hard to read?
| Are you guys generally search and read from here: https://docs.python.org/3/library/functions.html#filter ?
I found it is hard to read. Maybe it is my personal feeling. But I can easily read C++ and... |
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landlord1984 |
Data Science |
2 |
4,167 |
Jan-20-2017, 10:41 PM |
