repr

I have been reading about repr in Python. I was wondering what the application of the output of repr is. e.g. class A: pass repr(A) ='<class __main__.A at 0x6f570>' b=A() repr(b) = '<__main__.A instance at 0x74d78>' When would one be interested in '<class __main__.A at 0x6f570>' or '<__main__.A instance at 0x74d78>' ? unutbu Sometimes you have to deal with or present a byte string such as bob2='bob\xf0\xa4\xad\xa2' If you print this out (in Ubuntu) you get In [62]: print(bob2) bob𤭢 which is not very helpful to others trying to understand your byte string. In the comments, John points out that

According to the Python 2.7.12 documentation : !s (apply str() ) and !r (apply repr() ) can be used to convert the value before it is formatted. >>> import math >>> print 'The value of PI is approximately {}.'.format(math.pi) The value of PI is approximately 3.14159265359. >>> print 'The value of PI is approximately {!r}.'.format(math.pi) The value of PI is approximately 3.141592653589793. Interestingly, the converted value is the output of repr() , rather than str() . >>> str(math.pi) '3.14159265359' >>> repr(math.pi) '3.141592653589793' So what does "convert the value" mean here? Making it

I have a question, is there a way to "force" repr() to create always single quotes around a string? This happens when I only use repr() print repr("test") 'test' print repr("test'") "test'" print repr("test\"") 'test"' print repr("test'\"") 'test\'"' so the last one actually does, what I want, but I don't want to add always \\" to get the single quotes. Edit: I am not going to mark an answer as accepted since, as pointed out by @martijn-pieters, I was using repr() for purposes it is not intended for. Well, if your object is always a string you could do this: def repr_single(s): return "'" +

if I have a string with characters ( 0x61 0x62 0xD ), the repr function of this string will return 'ab\r' . Is there way to do reverse operation: if I have string 'ab\r' (with characters 0x61 0x62 0x5C 0x72 ), I need obtain string 0x61 0x62 0xD . I think what you're looking for is ast.literal_eval : >>> s = repr("ab\r") >>> s "'ab\\r'" >>> from ast import literal_eval >>> literal_eval(s) 'ab\r' 来源： https://stackoverflow.com/questions/24886123/reverse-repr-function-in-python

Is there a Java method that works like Python's repr? For example, assuming the function were named repr, "foo\n\tbar".repr() would return "foo\n\tbar" not foo bar as toString does. In some projects, I use the following helper function to accomplish something akin to Python's repr for strings: private static final char CONTROL_LIMIT = ' '; private static final char PRINTABLE_LIMIT = '\u007e'; private static final char[] HEX_DIGITS = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; public static String toPrintableRepresentation(String source) { if(

I'm trying to write a function to print a representation of common STL containers (vector, list, etc..). I gave the function a template parameter T which, for example, might represent vector. I'm having problems getting an iterator of type T. vector<int> v(10, 0); repr< vector<int> >(v); ... template <typename T> void repr(const T & v) { cout << "["; if (!v.empty()) { cout << ' '; T::iterator i; for (i = v.begin(); i != v.end()-1; ++i) { cout << *i << ", "; } cout << *(++i) << ' '; } cout << "]\n"; } ... brett@brett-laptop:~/Desktop/stl$ g++ -Wall main.cpp main.cpp: In function ‘void repr