Definite Iteration: When we know how many times we wanted to run a loop, then we use count-controlled loops such as for loops. It is also known as definite iteration. For example, Calculate the percentage of 50
change = [1, 'pennies', 2, 'dimes', 3, 'quarters'] # this first kind of for-loop goes through a list for number in the_count: print "This is count %d" % number # same as above for fruit in fruits: print "A fruit of type: %s" % fruit # also we can go through mixed lis...
-1,-1):yielddata[index]forcharinreverse('giraffe'):print(char)
Iterating over the items of an iterable in reverse or sorted order is also a common requirement in programming. To achieve this, you can combine a for loop with the built-in reversed() or sorted() function, respectively.Note: To learn more about reversed() and sorted(), check out the ...
()<<endl;vector<int>::iterator fwit;//定义正向迭代器vector<int>::reverse_iterator bwit;//定义反向迭代器cout<<"迭代器正向迭代: ";for(fwit=result.begin();fwit!=result.end();fwit++){//用迭代器遍历容器cout<<*fwit<<" ";}cout<<endl;cout<<"迭代器反向迭代: ";for(bwit=result....
pythonfor语句倒叙遍历 #PythonFor语句倒叙遍历在Python中,for语句是一种循环结构,用于遍历任何可迭代对象的元素。通常情况下,for语句是按顺序遍历一个序列中的元素,但有时我们也需要倒序遍历序列。在本文中,我们将介绍如何使用for语句进行倒序遍历,并通过代码示例来演示。 ## 什么是倒叙遍历?倒叙遍历是指从最后一个元...
$python-mtimeit-n1000000-s'importnumpyasnp''mylist=list(np.arange(0,200))''mylist.reverse()'1000000loops,bestof5:10.7usecperloop 这两种方法都可以反转列表,但需要注意的是内置函数reverse()会更改原始列表,而切片方法会创建一个新列表。 显然,内置函数reverse()比列表切片方法更快!
您还可以利用sorted()以排序和反向顺序遍历字符串: >>> >>> for vowel in sorted(vowels, reverse=True): ... print(vowel) ... ... u o i e a 该reverse给的说法sorted()可以让你排序iterables,包括字符串,按降序排列。因此,如果您需要按逆字母顺序排序的字符串字符,那么sorted()适合您。
To loop in the reverse direction, you can use Python's built-in reversed function:>>> colors = ["purple", "blue", "green", "pink", "red"] >>> for color in reversed(colors): ... print("I like", color) ... I like red I like pink I like green I like blue I like ...
尽管如此,生成器在内存使用和性能方面都更好。它们允许函数避免临时再做所有的工作,当结果的列表很大或者在处理每一个结果都需要很多时间时,这一点尤其有用。生成器将在loop迭代中处理一系列值的时间分布开来。 尽管如此,对于更多高级的应用,它们提供了一个更简单的替代方案来手动将类的对象保存到迭代中的状态。 有...