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How do I check if an index exists on a table field in MySQL?
...
Try:
SELECT * FROM information_schema.statistics
WHERE table_schema = [DATABASE NAME]
AND table_name = [TABLE NAME] AND column_name = [COLUMN NAME]
It will tell you if there is an index of any kind on a certain column wi...
What is Scala's yield?
...in F# would be
[ for a in args -> a.toUpperCase ]
or
from a in args select a.toUpperCase
in Linq.
Ruby's yield has a different effect.
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How to find the Windows version from the PowerShell command line
...fo. Powershell wrapper:
PS C:\> systeminfo /fo csv | ConvertFrom-Csv | select OS*, System*, Hotfix* | Format-List
OS Name : Microsoft Windows 7 Enterprise
OS Version : 6.1.7601 Service Pack 1 Build 7601
OS Manufacturer : Microsoft Corporation
OS Configuration : Stan...
How to check whether a string contains a substring in JavaScript?
...g we're extending the previous LSP
while (j > 0 && pattern.charAt(i) != pattern.charAt(j))
j = lsp[j - 1];
if (pattern.charAt(i) == pattern.charAt(j))
j++;
lsp.push(j);
}
// Walk through text string
var j = 0; // Number of chars matched in pattern
...
Best way to convert list to comma separated string in java [duplicate]
...mmons Lang (commons.apache.org/proper/commons-lang/apidocs/org/apache/…, char))
– Sigrist
Feb 8 '14 at 10:46
63
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半个汉字的校验与处理(C++) - C/C++ - 清泛网 - 专注C/C++及内核技术
...
// strSrc: 原始字符串
// nMaxLen: 截断后的最大长度
char *GetTruncate(char *strSrc, int nMaxLen)
{
if (strSrc == NULL || nMaxLen == 0)
{
return NULL;
}
int len = strlen(strSrc);
if (len == 0)
{
...
C语言面试那些事儿──一道指针与数组问题 - C/C++ - 清泛网 - 专注C/C++及内核技术
...─一道指针与数组问题首先看如下代码：int main(int argc, char** argv){ int a[5] = {1,2,3,4,5}; int* ptr = (int*)(&a + 1); ...首先看如下代码：
int main(int argc, char** argv)
{
int a[5] = {1,2,3,4,5};
int* ptr = (int*)(&a + 1);
printf("%d,%d\n", *(a+1...
std::string的截取字符串的方法 - C/C++ - 清泛网 - 专注C/C++及内核技术
...ndex).c_str();
//port
ip.substr(index + 1).c_str();
int find_first_of(char c, int start = 0):
查找字符串中第1个出现的c,由位置start开始。 如果有匹配，则返回匹配位置；否则，返回-1.默认情况下，start为0，函数搜索整个字符串。
int find...
sizeof、strlen简单总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
sizeof、strlen简单总结sizeofstrlenconst char* p4字符串长度std::string4字符串长度"......"字符串长度+1 (' 0')字符串长度
sizeof
strlen
const char* p
4
字符串长度
std::string
4
字符串长度
"......"
字符串长度+1 ('\0')...
error C2758: “ConstInit::cival”: 必须在构造函数基/成员初始值设定项列...
... int ival;
const int cival;
int &rival;
};
int main(int argc, char *argv[])
{
ConstInit ci;
}
这里引用类型rival以及const类型cival都没有在初始化列表中初始化，因此报错。解决办法就是在初始化列表中初始化这些特殊的类成员。如下...