我写了一个函数来获取格式的当前日期和时间:DD-MM-YYYY HH:MM:SS.它可以工作,但让我们说,它非常难看.我怎么能做同样的事情,但更简单？
string currentDateToString()
{
time_t now = time(0);
tm *ltm = localtime(&now);
string dateString = "", tmp = "";
tmp = numToString(ltm->tm_mday);
if (tmp.length() == 1)
tmp.insert(0, "0");
dateString += tmp;
dateString += "-";
tmp = numToString(1 + ltm->tm_mon);
if (tmp.length() == 1)
tmp.insert(0, "0");
dateString += tmp;
dateString += "-";
tmp = numToString(1900 + ltm->tm_year);
dateString += tmp;
dateString += " ";
tmp = numToString(ltm->tm_hour);
if (tmp.length() == 1)
tmp.insert(0, "0");
dateString += tmp; …最近我写了一个设置环境变量的脚本,看看:
#!/bin/bash
echo "Pass a path:"
read path
echo $path
defaultPath=/home/$(whoami)/Desktop
if [ -n "$path" ]; then
export my_var=$path
else
echo "Path is empty! Exporting default path ..."
export my_var=$defaultPath
fi
echo "Exported path: $my_var"
它工作得很好但问题是my_var只在本地可用,我的意思是在我运行脚本的控制台窗口中.
如何编写一个脚本,允许我导出可以随处看到的全局环境变量？
为什么这段代码不会抛出ArithmeticException？看一看:
public class NewClass {
public static void main(String[] args) {
// TODO code application logic here
double tab[] = {1.2, 3.4, 0.0, 5.6};
try {
for (int i = 0; i < tab.length; i++) {
tab[i] = 1.0 / tab[i];
}
} catch (ArithmeticException ae) {
System.out.println("ArithmeticException occured!");
}
}
}
我不知道!
我想选择一个日期(我的列是时间戳类型).但是当列中的是NULL日期时,我想返回一个空字符串.这该怎么做？我写了这个:
SELECT
CASE WHEN to_char(last_post, 'MM-DD-YYYY HH24:MI:SS') IS NULL THEN ''
ELSE to_char(last_post, 'MM-DD-YYYY HH24:MI:SS') AS last_post END
to_char(last_post, 'MM-DD-YYYY HH24:MI:SS') AS last_post, content
FROM topic;
但它告诉我一些错误,不知道为什么:
ERROR: syntax error at or near "as"
LINE 1: ...ELSE to_char(last_post, 'MM-DD-YYYY HH24:MI:SS') AS last_po...
^
我需要浏览网页上的所有页面.所有这些页面的左上角都有一个下拉框,包含所有可用的城市.我想通过选择此下拉框中的每个位置来访问每个页面.下拉框有一个滚动条,当我想选择它下面的选项时,它会给我异常消息:
Message: Element is not currently visible and so may not be interacted with
Stacktrace:
at fxdriver.preconditions.visible (file:///tmp/tmpHWLMyH/extensions/fxdriver@googlecode.com/components/command-processor.js:9981)
at DelayedCommand.prototype.checkPreconditions_ (file:///tmp/tmpHWLMyH/extensions/fxdriver@googlecode.com/components/command-processor.js:12517)
at DelayedCommand.prototype.executeInternal_/h (file:///tmp/tmpHWLMyH/extensions/fxdriver@googlecode.com/components/command-processor.js:12534)
at DelayedCommand.prototype.executeInternal_ (file:///tmp/tmpHWLMyH/extensions/fxdriver@googlecode.com/components/command-processor.js:12539)
at DelayedCommand.prototype.execute/< (file:///tmp/tmpHWLMyH/extensions/fxdriver@googlecode.com/components/command-processor.js:12481)
下面是代码:
#!/bin/env/python
# -*- coding: utf-8 -*-
import time
from selenium.webdriver.common.by import By
from selenium.webdriver.support.wait import WebDriverWait
from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import Select
def get_browser():
return webdriver.Firefox()
main_page_url = "http://example.com/"
basic_url = 'http://example.com/ogloszenia-kobiet.html'
def …不幸的是,新的一天带来了Python的新问题:/
我有一个用我用Java编写的其他应用程序生成的文件.这个应用程序生成带有一些数据的文件,它是一种随机的东西,因为我不能说每个文件有多少行.示例文件如下所示:
3 Sat Jan 21 00:00:00 2012
7 Sun Mar 11 00:00:00 2012
5 Fri Jan 1 00:00:00 2010
4 Sat Feb 5 00:00:00 2011
8 Sun Apr 11 00:00:00 2010
4 Wed Aug 24 00:00:00 2011
8 Sat Feb 20 00:00:00 2010
3 Thu Oct 13 00:00:00 2011
9 Fri Dec 17 00:00:00 2010
4 Tue Jul 20 00:00:00 2010
8 Fri Dec 2 00:00:00 2011
6 Mon May 31 00:00:00 2010
5 Mon May 16 00:00:00 2011 …我有一个C程序,它有2个参数,文件名和文本.我想在bash中编写一个脚本,它还带有2个参数,路径和文件扩展名,将遍历给定路径中的所有文件,并在C中作为参数文件提供给我的程序,仅包含givenextension和text.
继承我的C程序,真的没什么特别的:
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
if(argc < 3)
{
fprintf(stderr, "Give 2 args!\n");
exit(-1);
}
char *arg1 = argv[1];
char *arg2 = argv[2];
fprintf(stdout, "You gave: %s, %s\n", arg1, arg2);
return 0;
}
和我的bash脚本:
#!/bin/bash
path=$1
ext=$2
text=$3
for file in $path/*.$ext
do
./app |
{
echo $file
echo $text
}
done
我像这样使用它:./script /tmp txt hello它应该将txt来自/tmp和'hello'的所有文件作为参数提供给我的C程序.不,它只显示Give 2 args!:(请,帮助.
我有一张地图:TreeMap<String, Integer> m = new TreeMap<>();我有一个完整的字母和值,显示我的文字中每个字母的次数.
我想按递减计数顺序对该地图进行排序; 也就是说,最常见的字母在第一行,最后一行表示最不频繁的字母.如果两个字母具有相同的频率,那么字母表中首先出现的字母必须首先出现.怎么做？
我试过Comparator:
public int compare(String a, String b) {
if (base.get(a) >= base.get(b) && a.compareToIgnoreCase(b) < 0) {
return -1;
} else {
return 1;
}
}
但仍然,不是它,输出是:
D 3
E 3
A 2
S 5
伙计们......之前发现这个,这根本没有帮助.好的输出应该是:
S 5
D 3
E 3
A 2
我现在正在处理Python dicts.我写了一个代码:
import random
categories = {1 : "Antics", 2 : "Tickets", 3: "Moviez",
4 : "Music", 5 : "Photography", 6 : "Gamez", 7 : "Bookz",
8 : "Jewelry", 9 : "Computers", 10 : "Clothes"}
items = {"Picture" : 1, "Clock" : 1, "Ticket for Mettalica concert" : 2,
"Ticket for Iron Maiden concert" : 2, "Ticket for Placebo concert" : 2,
"The pianist" : 3, "Batman" : 3, "Spider-Man" : 3,
"WoW" : 6, "Cabal" : 6, "Diablo 3" …我有这样的课程:
class Product
{
public :
virtual double getPrice();
virtual void setPrice(double price);
};
class MusicProduct
{
protected:
string author;
double price;
public :
virtual string getAuthor();
virtual void setAuthor(string author);
~MusicProduct();
};
class CD : public MusicProduct, public Product
{
public :
string getAuthor();
void setAuthor(string author);
double getPrice();
void setPrice(double price);
};
string CD::getAuthor()
{
return MusicProduct::author;
}
void CD::setAuthor(string author)
{
MusicProduct:author = author;
}
void setPrice(double price)
{
MusicProduct::price = price;
}
double getPrice()
{
return …