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How do I parse a string to a float or int?
...
Python method to check if a string is a float:
def is_float(value):
try:
float(value)
return True
except:
return False
A longer and more accurate name for this function could be: is_convertible_to_float(value)
What is, and is not a float in Python may surpris...
how to clear the screen in python [duplicate]
... To avoid the 0 (system's return value) being shown, use absolutely_unused_variable = os.system("cls") or absolutely_unused_variable = os.system("clear")
– Shiva
Jul 4 '15 at 8:01
...
CMap用法 - C/C++ - 清泛网 - 专注C/C++及内核技术
...的效率。CMap就是对Hash表的一种实现。先上实例：
int _tmain(int argc, char* argv[])
{
//定义
typedef CMap<int, int, CString, CString> CMapInt;
CMapInt map;
//添加key，val
map.SetAt(1, "str1");
map.SetAt(2, "str2");
map.SetAt(3, "str3");
map.SetAt(1, "s...
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....
MFC的DDX和DDV技巧 - C/C++ - 清泛网 - 专注C/C++及内核技术
...件关系的成员变量的声明，代码：
// Dialog Data
//{{AFX_DATA(CMyDlg)
enum { IDD = IDD_DIALOG5 };
int m_edit;
//}}AFX_DATA
２． 在 .CPP文件中的类构造函数告终代码处，增加数据成员变量的一些初始化代码
CMyDlg::CMyDlg(CWnd* pParent )
...
CSS transition shorthand with multiple properties?
...n: height 0.3s ease-out, opacity 0.3s ease 0.5s;
Or just transition them all:
-webkit-transition: all 0.3s ease-out;
-moz-transition: all 0.3s ease-out;
-o-transition: all 0.3s ease-out;
transition: all 0.3s ease-out;
Here is a straightforward example. Here is another one with the delay propert...
Why do you need to create a cursor when querying a sqlite database?
...nnection object are nonstandard, i.e. they are not part of Python Database API Specification v2.0 (PEP 249).
As long as you use the standard methods of the Cursor object, you can be sure that if you switch to another database implementation that follows the above specification, your code will be fu...
PostgreSQL: insert from another table
...
Just supply literal values in the SELECT:
INSERT INTO TABLE1 (id, col_1, col_2, col_3)
SELECT id, 'data1', 'data2', 'data3'
FROM TABLE2
WHERE col_a = 'something';
A select list can contain any value expression:
But the expressions in the select list do not have to reference any columns i...
How to query nested objects?
...iness logic, then run a single query at the end: find(conditions, fields, callback);
– Ryan Wheale
May 21 '14 at 2:17
...
@ variables in Ruby on Rails
...cope (current block)
@title is an instance variable - and is available to all methods within the class.
You can read more here:
http://strugglingwithruby.blogspot.dk/2010/03/variables.html
In Ruby on Rails - declaring your variables in your controller as instance variables (@title) makes them ava...