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use the binary-only option for pip. For example, for mysqlclient:
*** pip install --only-binary :all: mysqlclient ***
3 years ago
Always check the standard libraries first.

*** import java.util.Arrays; ***
Then try:

*** System.out.println(Arrays.toString(array)); ***
or if your array contains other arrays as elements:

*** System.out.println(Arrays.deepToString(array)); ***
3 years ago
Three ways to check if a property is present in a javascript object:

*** !!obj.theProperty ***
Will convert the value to bool. returns true for all but the false value
*** 'theProperty' in obj ***
Will return true if the property exists, no matter its value (even empty)
*** obj.hasOwnProperty('theProperty') ***
Do not check the prototype chain. (since all objects have the toString method, 1 and 2 will return true on it, while 3 can return false on it.)
3 years ago
It is always cheaper/faster to append to a list and create a DataFrame in one go. Here is a program to append a data frame.
***
data = []
for a, b, c in some_function_that_yields_data():
data.append([a, b, c])

df = pd.DataFrame(data, columns=['A', 'B', 'C'])
***
3 years ago
For the data frame df use any of the following to get row counts.
***
len(df.index)
***
*** df.shape[0 ] ***
*** df[df.columns[0]].count() ***
3 years ago
The difference between g++ and gcc are:
g++ can compile any .c or .cpp files but they will be treated as C++ files only whereas gcc can compile any .c or .cpp files but they will be treated as C and C++ respectively.

Command to compile C++ program through g++ is *g++ fileName.cpp -o binary* whereas command to compile C program through gcc is *gcc fileName.c -o binary*
3 years ago
Use the following code to std: string to a pointer of characters or string data
***
const char* p_c_str = x.c_str();
const char* p_data = x.data();
char* p_writable_data = x.data(); // for non-const x from C++17
const char* p_x0 = &x[0];

char* p_x0_rw = &x[0]; // compiles iff x is not const...
***
3 years ago
Use the following code to std: string to a pointer of characters or string data
***
const char* p_c_str = x.c_str();
const char* p_data = x.data();
char* p_writable_data = x.data(); // for non-const x from C++17
const char* p_x0 = &x[0];

char* p_x0_rw = &x[0]; // compiles iff x is not const...
***
3 years ago
The short answer is that std::vector emplace_back forwards parameters to the constructor and avoids any extra copy or move operation required when using std::vector push_back. push_back may construct a temporary object, which then gets moved into the vector; whereas, emplace_back just forwards the argument(s) and constructs it directly in place with no copies or moves needed.
3 years ago
Here is the program to trim data.
***
#include
#include
#include

// trim from start (in place)
static inline void ltrim(std::string &s) {
s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](unsigned char ch) {
return !std::isspace(ch);
}));
}

// trim from end (in place)
static inline void rtrim(std::string &s) {
s.erase(std::find_if(s.rbegin(), s.rend(), [](unsigned char ch) {
return !std::isspace(ch);
}).base(), s.end());
}

// trim from both ends (in place)
static inline void trim(std::string &s) {
ltrim(s);
rtrim(s);
}

// trim from start (copying)
static inline std::string ltrim_copy(std::string s) {
ltrim(s);
return s;
}

// trim from end (copying)
static inline std::string rtrim_copy(std::string s) {
rtrim(s);
return s;
}

// trim from both ends (copying)
static inline std::string trim_copy(std::string s) {
trim(s);
return s;
}
***
3 years ago
Boost provides an algorithm of this
***
#include

std::string str = "HELLO, WORLD!";
boost::algorithm::to_lower(str); // modifies str
***
And for non-in-place
***
#include

const std::string str = "HELLO, WORLD!";
const std::string lower_str = boost::algorithm::to_lower_copy(str);
***
3 years ago
proccess.argv is an array containing command-line arguments. The first element will be 'node', the second element will be the name of the JavaScript file. The next element will be any additional command-line arguments.
***
// print process.argv
process.argv.forEach(function (val, index, array) {
console.log(index + ': ' + val);
});
***
3 years ago