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How do you create nested dict in Python?
...type 'dict'>, {'dict1': {'innerkey': 'value'}})
>>> dict(d) # but is exactly like a normal dictionary.
{'dict1': {'innerkey': 'value'}}
You can populate that however you want.
I would recommend in your code something like the following:
d = {} # can use defaultdict(dict) instead
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How to send email to multiple recipients using python smtplib?
After much searching I couldn't find out how to use smtplib.sendmail to send to multiple recipients. The problem was every time the mail would be sent the mail headers would appear to contain multiple addresses, but in fact only the first recipient would receive the email.
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How to delete duplicates on a MySQL table?
I need to DELETE duplicated rows for specified sid on a MySQL table.
25 Answers
25...
How to create default value for function argument in Clojure
...values.
(defn string->integer
([s] (string->integer s 10))
([s base] (Integer/parseInt s base)))
Note that assuming false and nil are both considered non-values, (if (nil? base) 10 base) could be shortened to (if base base 10), or further to (or base 10).
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Python-equivalent of short-form “if” in C++ [duplicate]
Is there a way to write this C/C++ code in Python?
a = (b == true ? "123" : "456" )
4 Answers
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Use a list of values to select rows from a pandas dataframe [duplicate]
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You can use isin method:
In [1]: df = pd.DataFrame({'A': [5,6,3,4], 'B': [1,2,3,5]})
In [2]: df
Out[2]:
A B
0 5 1
1 6 2
2 3 3
3 4 5
In [3]: df[df['A'].isin([3, 6])]
Out[3]:
A B
1 6 2
2 3 3
And to get the opposite use ~:
In [4]: df[~df['A'].isin([3, 6])]
Out[4]:
A B...
error: cannot dynamic_cast ‘b’ (of type ‘class Base*’) to type ‘c...
error: cannot dynamic_cast ‘b’ (of type ‘class Base*’) to type ‘class Derived*’ (source type is not polymorphic)在将父类型转换为子类型时,可以使用static_cast和dynamic_cast.如果使用dynamic_cast,它要求父类必须为多态的,即要求至少有一个虚函数,因此....
Debian/Linux下安装OpenJDK8 - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
Debian/Linux下安装OpenJDK8linux_install_openjdk8因为Debian11的源里不再带OpenJDK8了，需要手工来安装。下载安装包因为手工安装，所以部分依赖包需要自己下载。wget http: snapshot debian org archive debian-security 202202 因为Debian11的源里不再带Open...
What does the “~” (tilde/squiggle/twiddle) CSS selector mean?
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The ~ selector is in fact the General sibling combinator (renamed to Subsequent-sibling combinator in selectors Level 4):
The general sibling combinator is made of the "tilde" (U+007E, ~)
character that separates two sequences of simple selectors. The
eleme...
How do I check the difference, in seconds, between two dates?
There has to be an easier way to do this. I have objects that want to be refreshed every so often, so I want to record when they were created, check against the current timestamp, and refresh as necessary.
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