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Diffstat (limited to 'Doc/tutorial/controlflow.rst')
| -rw-r--r-- | Doc/tutorial/controlflow.rst | 52 |
1 files changed, 26 insertions, 26 deletions
diff --git a/Doc/tutorial/controlflow.rst b/Doc/tutorial/controlflow.rst index b0b4478..98f76ff 100644 --- a/Doc/tutorial/controlflow.rst +++ b/Doc/tutorial/controlflow.rst @@ -61,7 +61,7 @@ they appear in the sequence. For example (no pun intended): ... a = ['cat', 'window', 'defenestrate'] >>> for x in a: ... print(x, len(x)) - ... + ... cat 3 window 6 defenestrate 12 @@ -74,7 +74,7 @@ convenient:: >>> for x in a[:]: # make a slice copy of the entire list ... if len(x) > 6: a.insert(0, x) - ... + ... >>> a ['defenestrate', 'cat', 'window', 'defenestrate'] @@ -96,7 +96,7 @@ If you do need to iterate over a sequence of numbers, the built-in function 2 3 4 - + The given end point is never part of the generated list; ``range(10)`` generates @@ -104,13 +104,13 @@ The given end point is never part of the generated list; ``range(10)`` generates is possible to let the range start at another number, or to specify a different increment (even negative; sometimes this is called the 'step'):: - range(5, 10) + range(5, 10) 5 through 9 - range(0, 10, 3) + range(0, 10, 3) 0, 3, 6, 9 - range(-10, -100, -30) + range(-10, -100, -30) -10, -40, -70 To iterate over the indices of a sequence, you can combine :func:`range` and @@ -119,7 +119,7 @@ To iterate over the indices of a sequence, you can combine :func:`range` and >>> a = ['Mary', 'had', 'a', 'little', 'lamb'] >>> for i in range(len(a)): ... print(i, a[i]) - ... + ... 0 Mary 1 had 2 a @@ -135,12 +135,12 @@ A strange thing happens if you just print a range:: range(0, 10) In many ways the object returned by :func:`range` behaves as if it is a list, -but in fact it isn't. It is an object which returns the successive items of -the desired sequence when you iterate over it, but it doesn't really make -the list, thus saving space. +but in fact it isn't. It is an object which returns the successive items of +the desired sequence when you iterate over it, but it doesn't really make +the list, thus saving space. -We say such an object is *iterable*, that is, suitable as a target for -functions and constructs that expect something from which they can +We say such an object is *iterable*, that is, suitable as a target for +functions and constructs that expect something from which they can obtain successive items until the supply is exhausted. We have seen that the :keyword:`for` statement is such an *iterator*. The function :func:`list` is another; it creates lists from iterables:: @@ -177,7 +177,7 @@ following loop, which searches for prime numbers:: ... else: ... # loop fell through without finding a factor ... print(n, 'is a prime number') - ... + ... 2 is a prime number 3 is a prime number 4 equals 2 * 2 @@ -198,7 +198,7 @@ required syntactically but the program requires no action. For example:: >>> while True: ... pass # Busy-wait for keyboard interrupt (Ctrl+C) - ... + ... This is commonly used for creating minimal classes:: @@ -212,7 +212,7 @@ at a more abstract level. The :keyword:`pass` is silently ignored:: >>> def initlog(*args): ... pass # Remember to implement this! - ... + ... .. _tut-functions: @@ -229,7 +229,7 @@ boundary:: ... print(b, end=' ') ... a, b = b, a+b ... print() - ... + ... >>> # Now call the function we just defined: ... fib(2000) 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 @@ -300,7 +300,7 @@ Fibonacci series, instead of printing it:: ... result.append(b) # see below ... a, b = b, a+b ... return result - ... + ... >>> f100 = fib2(100) # call it >>> f100 # write the result [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89] @@ -436,7 +436,7 @@ calls. Here's an example that fails due to this restriction:: >>> def function(a): ... pass - ... + ... >>> function(0, a=0) Traceback (most recent call last): File "<stdin>", line 1, in ? @@ -487,7 +487,7 @@ Arbitrary Argument Lists ------------------------ .. index:: - statement: * + statement: * Finally, the least frequently used option is to specify that a function can be called with an arbitrary number of arguments. These arguments will be wrapped @@ -497,13 +497,13 @@ zero or more normal arguments may occur. :: def write_multiple_items(file, separator, *args): file.write(separator.join(args)) - + Normally, these ``variadic`` arguments will be last in the list of formal -parameters, because they scoop up all remaining input arguments that are +parameters, because they scoop up all remaining input arguments that are passed to the function. Any formal parameters which occur after the ``*args`` -parameter are 'keyword-only' arguments, meaning that they can only be used as +parameter are 'keyword-only' arguments, meaning that they can only be used as keywords rather than positional arguments. :: - + >>> def concat(*args, sep="/"): ... return sep.join(args) ... @@ -581,7 +581,7 @@ Documentation Strings single: strings, documentation Here are some conventions about the content and formatting of documentation -strings. +strings. The first line should always be a short, concise summary of the object's purpose. For brevity, it should not explicitly state the object's name or type, @@ -610,11 +610,11 @@ Here is an example of a multi-line docstring:: >>> def my_function(): ... """Do nothing, but document it. - ... + ... ... No, really, it doesn't do anything. ... """ ... pass - ... + ... >>> print(my_function.__doc__) Do nothing, but document it. |