我如何在0和1之间迭代0.1步?

这表示step参数不能为零:

for i in range(0, 1, 0.1):
    print(i)

当前回答

令人惊讶的是,在Python 3文档中还没有人提到推荐的解决方案:

参见: linspace菜谱展示了如何实现适用于浮点应用程序的惰性版本的range。

一旦定义,recipe就很容易使用,不需要numpy或任何其他外部库,只需要numpy.linspace()这样的函数。注意,第三个num参数指定所需值的数量,而不是step参数,例如:

print(linspace(0, 10, 5))
# linspace(0, 10, 5)
print(list(linspace(0, 10, 5)))
# [0.0, 2.5, 5.0, 7.5, 10]

下面我引用了Andrew Barnert的完整Python 3配方的修改版本:

import collections.abc
import numbers

class linspace(collections.abc.Sequence):
    """linspace(start, stop, num) -> linspace object

    Return a virtual sequence of num numbers from start to stop (inclusive).

    If you need a half-open range, use linspace(start, stop, num+1)[:-1].
    """
    def __init__(self, start, stop, num):
        if not isinstance(num, numbers.Integral) or num <= 1:
            raise ValueError('num must be an integer > 1')
        self.start, self.stop, self.num = start, stop, num
        self.step = (stop-start)/(num-1)
    def __len__(self):
        return self.num
    def __getitem__(self, i):
        if isinstance(i, slice):
            return [self[x] for x in range(*i.indices(len(self)))]
        if i < 0:
            i = self.num + i
        if i >= self.num:
            raise IndexError('linspace object index out of range')
        if i == self.num-1:
            return self.stop
        return self.start + i*self.step
    def __repr__(self):
        return '{}({}, {}, {})'.format(type(self).__name__,
                                       self.start, self.stop, self.num)
    def __eq__(self, other):
        if not isinstance(other, linspace):
            return False
        return ((self.start, self.stop, self.num) ==
                (other.start, other.stop, other.num))
    def __ne__(self, other):
        return not self==other
    def __hash__(self):
        return hash((type(self), self.start, self.stop, self.num))

其他回答

在'xrange([start], stop[, step])'基础上,你可以定义一个生成器,它接受并生成你选择的任何类型(坚持支持+和<的类型):

>>> def drange(start, stop, step):
...     r = start
...     while r < stop:
...         yield r
...         r += step
...         
>>> i0=drange(0.0, 1.0, 0.1)
>>> ["%g" % x for x in i0]
['0', '0.1', '0.2', '0.3', '0.4', '0.5', '0.6', '0.7', '0.8', '0.9', '1']
>>> 

令人惊讶的是,在Python 3文档中还没有人提到推荐的解决方案:

参见: linspace菜谱展示了如何实现适用于浮点应用程序的惰性版本的range。

一旦定义,recipe就很容易使用,不需要numpy或任何其他外部库,只需要numpy.linspace()这样的函数。注意,第三个num参数指定所需值的数量,而不是step参数,例如:

print(linspace(0, 10, 5))
# linspace(0, 10, 5)
print(list(linspace(0, 10, 5)))
# [0.0, 2.5, 5.0, 7.5, 10]

下面我引用了Andrew Barnert的完整Python 3配方的修改版本:

import collections.abc
import numbers

class linspace(collections.abc.Sequence):
    """linspace(start, stop, num) -> linspace object

    Return a virtual sequence of num numbers from start to stop (inclusive).

    If you need a half-open range, use linspace(start, stop, num+1)[:-1].
    """
    def __init__(self, start, stop, num):
        if not isinstance(num, numbers.Integral) or num <= 1:
            raise ValueError('num must be an integer > 1')
        self.start, self.stop, self.num = start, stop, num
        self.step = (stop-start)/(num-1)
    def __len__(self):
        return self.num
    def __getitem__(self, i):
        if isinstance(i, slice):
            return [self[x] for x in range(*i.indices(len(self)))]
        if i < 0:
            i = self.num + i
        if i >= self.num:
            raise IndexError('linspace object index out of range')
        if i == self.num-1:
            return self.stop
        return self.start + i*self.step
    def __repr__(self):
        return '{}({}, {}, {})'.format(type(self).__name__,
                                       self.start, self.stop, self.num)
    def __eq__(self, other):
        if not isinstance(other, linspace):
            return False
        return ((self.start, self.stop, self.num) ==
                (other.start, other.stop, other.num))
    def __ne__(self, other):
        return not self==other
    def __hash__(self):
        return hash((type(self), self.start, self.stop, self.num))

如果你经常这样做,你可能想保存生成的列表r

r=map(lambda x: x/10.0,range(0,10))
for i in r:
    print i

我认为NumPy有点过头了。

[p/10 for p in range(0, 10)]
[0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9]

一般来说,要做阶跃1/x直到y

x=100
y=2
[p/x for p in range(0, int(x*y))]
[0.0, 0.01, 0.02, 0.03, ..., 1.97, 1.98, 1.99]

(1/x在我测试时产生的舍入噪声更少)。

我知道我在这里迟到了,但这里有一个简单的生成器解决方案,在3.6中工作:

def floatRange(*args):
    start, step = 0, 1
    if len(args) == 1:
        stop = args[0]
    elif len(args) == 2:
        start, stop = args[0], args[1]
    elif len(args) == 3:
        start, stop, step = args[0], args[1], args[2]
    else:
        raise TypeError("floatRange accepts 1, 2, or 3 arguments. ({0} given)".format(len(args)))
    for num in start, step, stop:
        if not isinstance(num, (int, float)):
            raise TypeError("floatRange only accepts float and integer arguments. ({0} : {1} given)".format(type(num), str(num)))
    for x in range(int((stop-start)/step)):
        yield start + (x * step)
    return

然后你可以像原来的range()一样调用它…没有错误处理,但请告诉我是否有可以合理捕捉到的错误,我会更新。或者你可以更新它。这是StackOverflow。