Format Specifiers

Question

I'm wondering about something I saw with format specifiers. What I saw was this:

@"%03.1f", someFloat

I tested it and it returned in the log

"1.5"

What is this called, the thing with 03.1 between %f?

Answer 1

A width (%3f) says that we want three digits (positions) reserved for the output.

%3.1f -> (print as a floating point at least 3 wide and a precision of 1)

Read Format Specifiers

Answer 2

This is a basic question. It is from C language.

A default floating value can be formatted like:

%w.pf

Here:

w stands for width
p stands for precision

Please check C format specifiers

Example:

Printing 3.141592 using %f       displays 3.141592
Printing 3.141592 using %1.1f    displays 3.1
Printing 3.141592 using %1.2f    displays 3.14
Printing 3.141592 using %3.3f    displays 3.142
Printing 3.141592 using %4.4f    displays 3.1416
Printing 3.141592 using %4.5f    displays 3.14159
Printing 3.141592 using %09.3f   displays 00003.142
Printing 3.141592 using %-09.3f  displays 3.142
Printing 3.141592 using %9.3f    displays     3.142
Printing 3.141592 using %-9.3f   displays 3.142

Answer 3

%w.pf

where

w -> Minimum width of total value

p -> Exact number of decimal after .

float f = 2345.34567;
NSLog(@"%2.2f",f);  //Prints:   "2345.35"
NSLog(@"%.4f",f);   //Prints:   "2345.3556"
NSLog(@"%8.2f",f);  //Prints:   " 2345.35"(includes 1 space to make width of f  '8')
NSLog(@"%15.2f",f); //Prints:   "        2345.35"(includes 8 spaces to make width of f '15')