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How to select a single field for all documents in a MongoDB collection?
...nt such as:
db.student.find({}, {roll:1, _id:0})
The above statement will select all documents in the students collection, and the returned document will return only the roll field (and exclude the _id).
If we don't mention _id:0 the fields returned will be roll and _id. The '_id' field is always d...
Best way to repeat a character in C#
...turns
"aa"
from...
Is there a built-in function to repeat string or char in .net?
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Reading a string with scanf
...tring[0]). On the other hand, scanf("%s", &string) passes a pointer-to-char[256], but it points to the same place.
Then scanf, when processing the tail of its argument list, will try to pull out a char *. That's the Right Thing when you've passed in string or &string[0], but when you've pas...
Best practices/performance: mixing StringBuilder.append with String.concat
...end(sN).toString();
concat()
String s = s1.concat(s2);
String creates char[] array that can fit both s1 and s2. Copies s1 and s2 contents to this new array. Actually requires less work then + operator.
StringBuilder.append()
Maintains an internal char[] array that grows when needed. No extra ...
What's the need of array with zero elements?
...ther words, if you have:
struct something
{
/* other variables */
char data[];
}
struct something *var = malloc(sizeof(*var) + extra);
You can access var->data with indices in [0, extra). Note that sizeof(struct something) will only give the size accounting for the other variables, i....
uint8_t can't be printed with cout
...
It doesn't really print a blank, but most probably the ASCII character with value 5, which is non-printable (or invisible). There's a number of invisible ASCII character codes, most of them below value 32, which is the blank actually.
You have to convert aa to unsigned int to output t...
How to fix “Incorrect string value” errors?
...ify that the tables where the data is stored have the utf8 character set:
SELECT
`tables`.`TABLE_NAME`,
`collations`.`character_set_name`
FROM
`information_schema`.`TABLES` AS `tables`,
`information_schema`.`COLLATION_CHARACTER_SET_APPLICABILITY` AS `collations`
WHERE
`tables`.`table_sche...
@try - catch block in Objective-C
...
All work perfectly :)
NSString *test = @"test";
unichar a;
int index = 5;
@try {
a = [test characterAtIndex:index];
}
@catch (NSException *exception) {
NSLog(@"%@", exception.reason);
NSLog(@"Char at index %d cannot be found", index);
NSLog(@"Max inde...
Check if a string contains a number
...n, like this
>>> def hasNumbers(inputString):
... return any(char.isdigit() for char in inputString)
...
>>> hasNumbers("I own 1 dog")
True
>>> hasNumbers("I own no dog")
False
Alternatively you can use a Regular Expression, like this
>>> import re
>&g...
Reading string from input with space character? [duplicate]
...s per your need.
Use:
scanf ("%[^\n]%*c", name);
The [] is the scanset character. [^\n] tells that while the input is not a newline ('\n') take input. Then with the %*c it reads the newline character from the input buffer (which is not read), and the * indicates that this read in input is discar...