Why is PHP printing my number in scientific notation, when I specified it as .000021?
Use number_format() to get what you’re after: print number_format($var, 5); Also check sprintf()
syntax
When were the ‘and’ and ‘or’ alternative tokens introduced in C++?
From the first ISO C++ standard C++98, this is described in 2.5/ Alternative tokens [lex.digraph]: Alternative token representations are provided for some operators and punctuators. In all respects of the language, each alternative token behaves the same, respectively, as its primary token, except for its spelling. The set of alternative tokens is defined in Table … Read more
What is the difference between these (bCondition == NULL) and (NULL==bCondition)?
The use of NULL == condition provides more useful behaviour in the case of a typo, when an assignment operator = is accidentally used rather then the comparison operator ==: if (bCondition = NULL) // typo here { // code never executes } if (NULL = bCondition) // error -> compiler complains { // … … Read more
What’s the syntax to import a class in a default package in Java? [duplicate]
You can’t import classes from the default package. You should avoid using the default package except for very small example programs. From the Java language specification: It is a compile time error to import a type from the unnamed package.
Immediate function invocation syntax
From Douglass Crockford’s style convention guide: (search for “invoked immediately”) When a function is to be invoked immediately, the entire invocation expression should be wrapped in parens so that it is clear that the value being produced is the result of the function and not the function itself. So, basically, he feels it makes more … Read more
Test for non-zero length string in Bash: [ -n “$var” ] or [ “$var” ]
Edit: This is a more complete version that shows more differences between [ (aka test) and [[. The following table shows that whether a variable is quoted or not, whether you use single or double brackets and whether the variable contains only a space are the things that affect whether using a test with or … Read more
Language support for chained comparison operators (x < y < z)
It should be more common, but I suspect it is not because it makes parsing languages more complex. Benefits: Upholds the principle of least surprise Reads like math is taught Reduces cognitive load (see previous 2 points) Drawbacks: Grammar is more complex for the language Special case syntactic sugar As to why not, my guesses … Read more
Difference between using bracket (`[]`) and dot (`.`) notation [duplicate]
Accessing members with . is called dot notation. Accessing them with [] is called bracket notation. The dot notation only works with property names which are valid identifier names [spec], so basically any name that would also be a valid variable name (a valid identifier, see also What characters are valid for JavaScript variable names?) … Read more
What is the use of the square brackets [] in sql statements?
The brackets are required if you use keywords or special chars in the column names or identifiers. You could name a column [First Name] (with a space) – but then you’d need to use brackets every time you referred to that column. The newer tools add them everywhere just in case or for consistency.
Bash syntax error: unexpected end of file
I think file.sh is with CRLF line terminators. run dos2unix file.sh then the problem will be fixed. You can install dos2unix in ubuntu with this: sudo apt-get install dos2unix