range()函式的使用

• 首先利用help(range)來看一下python中的詳細解釋：

>>>help(range)
>Help on class range in module builtins:

class range(object)
 |  range(stop) -> range object
 |  range(start, stop[, step]) -> range object
 |  
 |  Return an object that produces a sequence of integers from start (inclusive)
 

 |  to stop (exclusive) by step.  range(i, j) produces i, i+1, i+2, ..., j-1.
 |  start defaults to 0, and stop is omitted!  range(4) produces 0, 1, 2, 3.
 |  These are exactly the valid indices for a list of 4 elements.
 |  When step is given, it specifies the increment (or decrement).
 |  
 |  Methods defined here:
 

 |  
 |  __contains__(self, key, /)
 |      Return key in self.
 |  
 |  __eq__(self, value, /)
 |      Return self==value.
 |  
 |  __ge__(self, value, /)
 |      Return self>=value.
 |  
 |  __getattribute__(self, name, /)
 |      Return getattr(self, name).
 |  
 |  __getitem__(self, key, /)
 |      Return self[
 
key].
 |  
 |  __gt__(self, value, /)
 |      Return self>value.
 |  
 |  __hash__(self, /)
 |      Return hash(self).
 |  
 |  __iter__(self, /)
 |      Implement iter(self).
 |  
 |  __le__(self, value, /)
 |      Return self<=value.
 |  
 |  __len__(self, /)
 |      Return len(self).
 |  
 |  __lt__(self, value, /)
 |      Return self<value.
 |  
 |  __ne__(self, value, /)
 |      Return self!=value.
 |  
 |  __new__(*args, **kwargs) from builtins.type
 |      Create and return a new object.  See help(type) for accurate signature.
 |  
 |  __reduce__(...)
 |      helper for pickle
 |  
 |  __repr__(self, /)
 |      Return repr(self).
 |  
 |  __reversed__(...)
 |      Return a reverse iterator.
 |  
 |  count(...)
 |      rangeobject.count(value) -> integer -- return number of occurrences of value
 |  
 |  index(...)
 |      rangeobject.index(value, [start, [stop]]) -> integer -- return index of value.
 |      Raise ValueError if the value is not present.
 |  
 |  ----------------------------------------------------------------------
 |  Data descriptors defined here:
 |  
 |  start
 |  
 |  step
 |  
 |  stop

• 作用 產生一系列整數，返回一個range物件

• 語法：

  range(start,end,step) range(start,end) range(end) range函式中帶有三個引數：start、end、step。 例如：產生數字0-1的列表：

>>> list(range(0,10,1))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

>>> list(range(0,10))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

>>> list(range(10))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

三種情況輸出結果相同 start 起始值（包含），end 終止值（不包含），step 步長。

• range(start,end)——省卻step時，預設步長為1；
• range(end)——省卻step、start時，預設步長為1，起始值為0 注意：step的值不能為0或者浮點數

>>> list(range(2,10,2))
[2, 4, 6, 8]

>>> list(range(2,10,2.5))
Traceback (most recent call last):
  File "<pyshell#16>", line 1, in <module>
    list(range(2,10,2.5))
TypeError: 'float' object cannot be interpreted as an integer