#!/usr/bin/env python import matplotlib.pyplot as plt import datetime ax = tuple([datetime.datetime(2015, 10, 27, 17, 17, sec) for sec in range(1,10)]) print ax ay = tuple(range(1,10)) plt.plot(ax,ay) # Beautify the display format plt.gcf().autofmt_xdate() plt.show()When doing enough zoom in, it will display in macro seconds resolution. When zooming out enough,it will display dates.
#include <stdio.h>
#define TEST_3
void FuncA ()
{
#ifdef TEST_0
// 0 value initialization only happen once if defined 'static'.
static int StaticVar=0;
#endif
#ifdef TEST_1
// 0 value initialization happen every time when FuncA is called.
int StaticVar=0;
#endif
#ifdef TEST_2
// When not give inital value, system set StaticVar to '0'
// Changed value will stay next time when FuncA is called as StaticVar
// is defined with keyward 'static'.
static int StaticVar;
printf("StaticVar is : %d\n",StaticVar);
StaticVar = 2;
#endif
#ifdef TEST_3
// When no 'static', system set StaticVar to a random value.
// (I think it depends on what value in stack.)
// But in test it seems, StaticVar keep same value as it's retrieving
// value from same postion in stack.
int StaticVar;
printf("StaticVar is : %d\n",StaticVar);
StaticVar = 3;
#endif
printf("StaticVar is : %d\n",StaticVar);
StaticVar++;
}
void main()
{
FuncA();
FuncA();
FuncA();
FuncA();
FuncA();
FuncA();
printf ("====Done====\n");
}
The results after defining different test cases:qyang@lubuntu-laptop:~$ ./Learn_static StaticVar is : 0 StaticVar is : 1 StaticVar is : 2 StaticVar is : 3 StaticVar is : 4 StaticVar is : 5 ====Done====Test_1
qyang@lubuntu-laptop:~$ ./Learn_static StaticVar is : 0 StaticVar is : 0 StaticVar is : 0 StaticVar is : 0 StaticVar is : 0 StaticVar is : 0 ====Done====Test_2
qyang@lubuntu-laptop:~$ ./Learn_static StaticVar is : 0 StaticVar is : 2 StaticVar is : 3 StaticVar is : 2 StaticVar is : 3 StaticVar is : 2 StaticVar is : 3 StaticVar is : 2 StaticVar is : 3 StaticVar is : 2 StaticVar is : 3 StaticVar is : 2 ====Done====Test_3
qyang@lubuntu-laptop:~$ ./Learn_static StaticVar is : 134513947 StaticVar is : 3 StaticVar is : 4 StaticVar is : 3 StaticVar is : 4 StaticVar is : 3 StaticVar is : 4 StaticVar is : 3 StaticVar is : 4 StaticVar is : 3 StaticVar is : 4 StaticVar is : 3 ====Done====
When you have a pointer to an object, the object may actually be of a class that is derived from the class of the pointer (e.g., a Vehicle* that is actually pointing to a Car object; this is called “polymorphism”多态性). Dynamic binding is a result of virtual functions.
cp {*.doc,*.pdf} ~
This will copy anything ending with .doc or .pdf to the users home directory. Note that spaces are not allowed after the commas (or anywhere else).find -regex ".*\.\(xls\|csv\)"find -name "*.xls" -o -name "*.csv"
In [33]: 10*math.log(10,10) Out[33]: 10.0 In [34]: 10*math.log(2,10) 2 times Out[34]: 3.0102999566398116 how 3 dB derived
git fetch --dry-run
Useful Tips Section
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The tag defines a hyperlink, which is used to link from one page to another. In HTML 4.01, the tag could be either a hyperlink or an anchor. In HTML5, the tag is always a hyperlink, but if it has no href attribute, it is only a placeholder for a hyperlink. HTML5 has some new attributes, and some HTML 4.01 attributes are no longer supported.
#!/bin/sh xrdb $HOME/.Xresources xsetroot -solid grey -cursor_name left_ptr autocutsel -fork lxsession -s Lubuntu -e LXDE
GNOME Keyring is a collection of components in GNOME that store secrets, passwords, keys, certificates and make them available to applications.
GNOME Keyring is integrated with the user's login, so that their secret storage can be unlocked when the user logins into their session.
GNOME Keyring is based around a standard called PKCS#11, which is a standard way for applications to manage certificates and keys on smart cards or secure storage.
