I'm reading someone elses code and they are using %#-1 to format an integer. I can't find anything on Google since it ignores symbols. Anyone else had more experience at string formatting than me?
[NSString stringWithFormat:#"%#-1", subnumber]
Thanks!
According to the specification:
Each conversion specification is introduced by the '%' character, or by the character sequence "%n$", after which the following appear in sequence:
Zero or more flags (in any order), which modify the meaning of the conversion specification.
An optional minimum field width. If the converted value has fewer bytes than the field width, it shall be padded with spaces by default on the left; it shall be padded on the right if the left-adjustment flag ( '-' ), described below, is given to the field width. The field width takes the form of an asterisk ( '*' ), described below, or a decimal integer.
An optional precision that gives the minimum number of digits to appear for the d, i, o, u, x, and X conversion specifiers; the number of digits to appear after the radix character for the a, A, e, E, f, and F conversion specifiers; the maximum number of significant digits for the g and G conversion specifiers; or the maximum number of bytes to be printed from a string in the s [XSI] [Option Start] and S [Option End] conversion specifiers. The precision takes the form of a period ( '.' ) followed either by an asterisk ( '*' ), described below, or an optional decimal digit string, where a null digit string is treated as zero. If a precision appears with any other conversion specifier, the behavior is undefined.
An optional length modifier that specifies the size of the argument.
A conversion specifier character that indicates the type of conversion to be applied.
We're using a conversion of the first type, since there's no dollar sign in here. Note the words in sequence at the top of the above list. The # is a conversion specifier character (as mentioned here), which indicates that we should access the value passed in as an NSObject and read its description property. Since we've already reached the last bullet point, the format code actually ends after the # symbol, and as #Kevin Ballard pointed out, the -1 is parsed as literal text.
That's just going to print "NUM-1" (where NUM is the number). To give an example, if the number is 5, that will print "5-1".
When using format strings, any modifiers to the format token must occur before the format type specifier. In this case, that means any modifiers to the %# token must occur between the % and the # (though I'm not sure if there are actually any modifiers that %# accepts).
subnumber is probably object of class like NSNumber. Like we use %d for int, %f for float, %# is place holder for a refrence. In that case
NSNumber *subnumber = [NSNumber numberWithInt:5];
NSLog([NSString stringWithFormat:#"%#-1", subnumber]);
will print '5-1'
Related
I know how to return a Unicode character from a code point. That's not what I'm after. What I want to know is how to return the name associated with a particular code point. For example, The code point for 🍀 is 1F340. And its name is FOUR LEAF CLOVER. Is it possible for us to return this name with its code point? I've read about 100 topics involving Unicode. But I haven't see one discussing my question. I hope that's possible.
Thank you for your help.
Have you considered the ICU library? It offers the following C API: http://icu-project.org/apiref/icu4c/uchar_8h.html#aa488f2a373998c7decb0ecd3e3552079
int32_t u_charName(
UChar32 code,
UCharNameChoice nameChoice,
char* buffer,
int32_t bufferLength,
UErrorCode* pErrorCode)
Retrieve the name of a Unicode character.
Depending on nameChoice, the character name written into the buffer is the "modern" name or the name that was defined in Unicode version 1.0. The name contains only "invariant" characters like A-Z, 0-9, space, and '-'. Unicode 1.0 names are only retrieved if they are different from the modern names and if the data file contains the data for them. gennames may or may not be called with a command line option to include 1.0 names in unames.dat.
Parameters
code The character (code point) for which to get the name. It must be 0<=code<=0x10ffff.
nameChoice Selector for which name to get.
buffer Destination address for copying the name. The name will always be zero-terminated. If there is no name, then the buffer will be set to the empty string.
bufferLength ==sizeof(buffer)
pErrorCode Pointer to a UErrorCode variable; check for U_SUCCESS() after u_charName() returns.
Returns
The length of the name, or 0 if there is no name for this character. If the bufferLength is less than or equal to the length, then the buffer contains the truncated name and the returned length indicates the full length of the name. The length does not include the zero-termination.
ICU is the right approach, but it's even simpler than Chris said. Foundation includes ICU already, for various text processing functions, including CFStringTransform(). Its transform parameter accepts "any valid ICU transform ID defined in the ICU User Guide for Transforms".
One of ICU's transforms is Any-Name:
Converts between characters and their Unicode names in curly braces. For example:
., ⇆ {FULL STOP}{COMMA}
(The syntax isn't exactly as documented, but it's close enough you can figure it out.)
There's also an Any-Hex transform which can be used for translating to/from the codepoint hex value.
Is there a way to use scientific notation in objective c and have it display three significant digits only? What I am current using is:
string = [NSString stringWithFormat:#"%e", floatNumber];
// floatNumber = 100000; string = 1.000000e+06
I just want string = 1.00e+06
Use the format specifier ".2" as follows:
string = [NSString stringWithFormat:#"%.2e", floatNumber];
From apple's documentation:
The format specifiers supported by the NSString formatting methods and CFString formatting functions follow the IEEE printf specification...
And from the IEEE printf specification, if you read under the Description section, you will find:
e, E
The double argument shall be converted in the style "[-]d.ddde±dd", where there is one digit before the radix character (which is non-zero if the argument is non-zero) and the number of digits after it is equal to the precision; if the precision is missing, it shall be taken as 6; if the precision is zero and no '#' flag is present, no radix character shall appear. The low-order digit shall be rounded in an implementation-defined manner. The E conversion specifier shall produce a number with 'E' instead of 'e' introducing the exponent. The exponent shall always contain at least two digits. If the value is zero, the exponent shall be zero.
I read data from a excel file.
The cols of internal table all are char128, there are 2 cols contain only digital with decimal point. So I need to check the fields only contain digital or digital with decimal point.
The function module NUMERIC_CHECK, just can check only digital, if the digital with decimal point it will be useless.
You may use CO (contains only):
IF value CO '1234567890.'.
"OK
ELSE.
"Error"
ENDIF.
Maybe you need also a space in your IF _ CO-statement.
This check does not detect multiple decimals points (e.g. 123.45.67.89).
Newer versions of ABAP support regular expressions.
If you have also spaces in your string, you may add them into the CO-value:: IF value CO '1234567890 .'.
You might try to use REGEX. The report DEMO_REGEX_TOY lets you input strings and test regular expressions against them.
Someone more experienced with REGEX in general might be able to make this a little more versatile but here's what I came up with:
-?[0-9]+(\.[0-9]*)?
-? Optionally match the '-' character (allows for negatives or non-negatives
[0-9]+ matches digits (the + makes it match 1 or more)
\.? optionally matches the '.' character (the \ is needed as '.' is an operator)
([0-9]+)? optionally matches any digits after the decimal
if you want to check if the string is a valid decimal, you could use the following module function : 'HRCM_STRING_TO_AMOUNT_CONVERT', which allow you to convert a string to its numeric counterpart, given the string, the decimal separator and the thousand separator.
regards
Another way to check for number:
data: float_value type f.
try.
float_value = <your string value here>.
catch cx_sy_conversion_no_number.
" not a valid number
endtry.
I'm looking at inherited code and I found this in a vb.net windows form:
New System.Drawing.SizeF(6.0!, 13.0!)
My question is, what is the significance of the ! (exclamation) operator here? Most of my searching for the exclamation operator ends up returning recordset format or the ! gets ignored in the search and I get hundreds of unrelated items.
It's to force the literal to be a Single.
Visual Basic supports Type Characters:
In addition to specifying a data type in a declaration statement, you can force the data type of some programming elements with a type character. The type character must immediately follow the element, with no intervening characters of any kind.
and:
Literals can also use the identifier type characters (%, &, #, !, #, $), as can variables, constants, and expressions. However, the literal type characters (S, I, L, D, F, R, C) can be used only with literals.
In this case, the ! stands for Single:
Type Characters. Appending the literal type character F to a literal forces it to the Single data type. Appending the identifier type character ! to any identifier forces it to Single.
(emphasis mine)
It is a type character. It means that 6.0 is a Single data type.
http://msdn.microsoft.com/en-us/library/s9cz43ek.aspx show the type characters.
I'm finding that Char fields are being padded.
Is there any way to stop this happening.
I've tried using the property
SET PROPERTY "sql.enforce_strict_size" FALSE
but doesn't seem to help.
Indeed, the MySQL docs specify that "When CHAR values are retrieved, trailing spaces are removed." This is odd, as other databases seem to always keep the padding (i can confirm that for Oracle). The SQL-92 standard indicates that right-padded spaces are part of the char, for example in the definition of the CAST function on p. 148. When source (SV=source value) and target (TV=target value, LTD=length of target datatype), then:
ii) If the length in characters of SV is larger than LTD, then
TV is the first LTD characters of SV. If any of the re-
maining characters of SV are non-<space> characters, then a
completion condition is raised: warning-string data, right
truncation.
iii) If the length in characters M of SV is smaller than LTD,
then TV is SV extended on the right by LTD-M <space>s.
Maybe that's just another one of MySQL's many oddities and gotchas.
And to answer your question: if you don't want the trailing spaces, you should use VARCHAR instead.
I thought 'char' by definition are space padded to fill the field. They are considered fixed lenght and will be space padded to be fixed length.
The data type 'varchar' is defined as variable char where they are not space padded to fill the field.
I could be wrong though since I normally work on SQL Server.