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| -rw-r--r-- | Doc/tut/tut.tex | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex index f79a183..a60d442 100644 --- a/Doc/tut/tut.tex +++ b/Doc/tut/tut.tex @@ -2765,9 +2765,9 @@ resulting from this formatting operation. One question remains, of course: how do you convert values to strings? Luckily, Python has ways to convert any value to a string: pass it to -the \function{repr()} or \function{str()} functions, or just write -the value between reverse quotes (\code{``}, equivalent to -\function{repr()}). +the \function{repr()} or \function{str()} functions. Reverse quotes +(\code{``}) are equivalent to \function{repr()}, but their use is +discouraged. The \function{str()} function is meant to return representations of values which are fairly human-readable, while \function{repr()} is @@ -2786,28 +2786,26 @@ Some examples: >>> s = 'Hello, world.' >>> str(s) 'Hello, world.' ->>> `s` +>>> repr(s) "'Hello, world.'" >>> str(0.1) '0.1' ->>> `0.1` +>>> repr(0.1) '0.10000000000000001' >>> x = 10 * 3.25 >>> y = 200 * 200 ->>> s = 'The value of x is ' + `x` + ', and y is ' + `y` + '...' +>>> s = 'The value of x is ' + repr(x) + ', and y is ' + repr(y) + '...' >>> print s The value of x is 32.5, and y is 40000... ->>> # Reverse quotes work on other types besides numbers: -... p = [x, y] ->>> ps = repr(p) ->>> ps -'[32.5, 40000]' ->>> # Converting a string adds string quotes and backslashes: +>>> # The repr() of a string adds string quotes and backslashes: ... hello = 'hello, world\n' ->>> hellos = `hello` +>>> hellos = repr(hello) >>> print hellos 'hello, world\n' ->>> # The argument of reverse quotes may be a tuple: +>>> # The argument to repr() may be any Python object: +... repr(x, y, ('spam', 'eggs')) +"(32.5, 40000, ('spam', 'eggs'))" +>>> # reverse quotes are convenient in interactive sessions: ... `x, y, ('spam', 'eggs')` "(32.5, 40000, ('spam', 'eggs'))" \end{verbatim} @@ -2817,9 +2815,9 @@ Here are two ways to write a table of squares and cubes: \begin{verbatim} >>> import string >>> for x in range(1, 11): -... print string.rjust(`x`, 2), string.rjust(`x*x`, 3), +... print string.rjust(repr(x), 2), string.rjust(repr(x*x), 3), ... # Note trailing comma on previous line -... print string.rjust(`x*x*x`, 4) +... print string.rjust(repr(x*x*x), 4) ... 1 1 1 2 4 8 @@ -3357,7 +3355,7 @@ example: ... def __init__(self, value): ... self.value = value ... def __str__(self): -... return `self.value` +... return repr(self.value) ... >>> try: ... raise MyError(2*2) |