Python _collections_abc.Mapping方法代码示例

# 需要导入模块: import _collections_abc [as 别名]
# 或者: from _collections_abc import Mapping [as 别名]
def format_string(f, val, grouping=False, monetary=False):
    """Formats a string in the same way that the % formatting would use,
    but takes the current locale into account.

    Grouping is applied if the third parameter is true.
    Conversion uses monetary thousands separator and grouping strings if
    forth parameter monetary is true."""
    percents = list(_percent_re.finditer(f))
    new_f = _percent_re.sub('%s', f)

    if isinstance(val, _collections_abc.Mapping):
        new_val = []
        for perc in percents:
            if perc.group()[-1]=='%':
                new_val.append('%')
            else:
                new_val.append(_format(perc.group(), val, grouping, monetary))
    else:
        if not isinstance(val, tuple):
            val = (val,)
        new_val = []
        i = 0
        for perc in percents:
            if perc.group()[-1]=='%':
                new_val.append('%')
            else:
                starcount = perc.group('modifiers').count('*')
                new_val.append(_format(perc.group(),
                                      val[i],
                                      grouping,
                                      monetary,
                                      *val[i+1:i+1+starcount]))
                i += (1 + starcount)
    val = tuple(new_val)

    return new_f % val 

# 需要导入模块: import _collections_abc [as 别名]
# 或者: from _collections_abc import Mapping [as 别名]
def update(*args, **kwds):
        '''Like dict.update() but add counts instead of replacing them.

        Source can be an iterable, a dictionary, or another Counter instance.

        >>> c = Counter('which')
        >>> c.update('witch')           # add elements from another iterable
        >>> d = Counter('watch')
        >>> c.update(d)                 # add elements from another counter
        >>> c['h']                      # four 'h' in which, witch, and watch
        4

        '''
        # The regular dict.update() operation makes no sense here because the
        # replace behavior results in the some of original untouched counts
        # being mixed-in with all of the other counts for a mismash that
        # doesn't have a straight-forward interpretation in most counting
        # contexts.  Instead, we implement straight-addition.  Both the inputs
        # and outputs are allowed to contain zero and negative counts.

        if not args:
            raise TypeError("descriptor 'update' of 'Counter' object "
                            "needs an argument")
        self, *args = args
        if len(args) > 1:
            raise TypeError('expected at most 1 arguments, got %d' % len(args))
        iterable = args[0] if args else None
        if iterable is not None:
            if isinstance(iterable, _collections_abc.Mapping):
                if self:
                    self_get = self.get
                    for elem, count in iterable.items():
                        self[elem] = count + self_get(elem, 0)
                else:
                    super(Counter, self).update(iterable) # fast path when counter is empty
            else:
                _count_elements(self, iterable)
        if kwds:
            self.update(kwds) 

# 需要导入模块: import _collections_abc [as 别名]
# 或者: from _collections_abc import Mapping [as 别名]
def subtract(*args, **kwds):
        '''Like dict.update() but subtracts counts instead of replacing them.
        Counts can be reduced below zero.  Both the inputs and outputs are
        allowed to contain zero and negative counts.

        Source can be an iterable, a dictionary, or another Counter instance.

        >>> c = Counter('which')
        >>> c.subtract('witch')             # subtract elements from another iterable
        >>> c.subtract(Counter('watch'))    # subtract elements from another counter
        >>> c['h']                          # 2 in which, minus 1 in witch, minus 1 in watch
        0
        >>> c['w']                          # 1 in which, minus 1 in witch, minus 1 in watch
        -1

        '''
        if not args:
            raise TypeError("descriptor 'subtract' of 'Counter' object "
                            "needs an argument")
        self, *args = args
        if len(args) > 1:
            raise TypeError('expected at most 1 arguments, got %d' % len(args))
        iterable = args[0] if args else None
        if iterable is not None:
            self_get = self.get
            if isinstance(iterable, _collections_abc.Mapping):
                for elem, count in iterable.items():
                    self[elem] = self_get(elem, 0) - count
            else:
                for elem in iterable:
                    self[elem] = self_get(elem, 0) - 1
        if kwds:
            self.subtract(kwds)