In Python, list comprehension is a concise way to create a newlistbased on the values of an existing list. List comprehension is often used for its brevity and readability compared to traditionalfor-loop. This Python tutorial discusses what is list comprehension, and its syntax with easy-to-un...
Python 不喜欢 FP 的，而且 map / filter 是惰性的，list comprehension不是。循环比 list comprehension...
Here, list comprehension checks if the number from range(1, 10) is even or odd. If even, it appends the number in the list. Note: The range() function generates a sequence of numbers. To learn more, visit Python range(). if...else With List Comprehension Let's use if...else wi...
很多时候我们需要创建一个满足特定要求的新列表,不得不用for循环来创建,而用列表推导式来表达只需要一行代码即可。列表推导式另一个优点是相比于for循环更高效,因为列表推导式在执行时调用的是Python的底层C代码,而for循环则是用Python代码来执行。比如我们需要创建一个包含平方数的列表,用for循环实现方式如下: ...
%timeit [add(x)forxinarray]#1000 loops, best of 3: 180 us per loop 总上所述:简单的循环映射操作,我们建议用列表推导形式,其效率更高,速度更快。复杂的循环映射操作,我们建议用for循环,这样的代码更加易读易懂。而对于map方法,我们认为这是一种过时的写法,应当少用,甚至不用。
/usr/bin/python data = ["even" if i % 2 == 0 else "odd" for i in range(7)] print(data) In the example, we transform the values into"even"and"odd"values using the list comprehension. $ ./infront.py ['even', 'odd', 'even', 'odd', 'even', 'odd', 'even']...
如果想了解list comprehension原理的东西,这个人文章写得很清楚:http://blog.chinaunix.net/uid-28631822-id-3488324.html 5.实践: 在来一道题,摘自《Python基础教程》: >>> girls = ['alice','bernice','clarice']>>> boys = ['chris','arnold','bob']>>> [b+'+'+gforbinboysforgingirlsifb[0]=...
for item in iterable→ Loops through the given iterable (e.g., list, tuple, range). if condition(optional)→ Filters elements based on a condition. Examples 1. Creating a List Using List Comprehension We can generate a new list using list comprehension instead of using a loop. ...
non_negative = [x if x >= 0 else 0 for x in numbers] # Print the new list print(non_negative) Output: [0, 13, 0, 17, 0, 0, 14] Explanation: The list comprehension iterates over 'numbers' and checks if each number 'x' is non-negative ('x >= 0'). If the condition is...
Python if...else Statement Python for Loop Python while Loop Python break and continue Python pass Statement Python Data types Python Numbers and Mathematics Python List Python Tuple Python String Python Set Python Dictionary Python Functions Python Functions Python Function Arguments Python Variable Scope...