I have 2 variables, say x and y, and I need to check which of them is None if x is None and y is None: # code here else: if x is not None and y is not None: # code here else: if x is None: # code here if y is None: # code here Is there a better approach to do this? I am looking for a shorter IF ELSE structure. Keeping the order you
我有2个变量，例如x和y，我需要检查其中哪些是None if x is None and y is None: # code here else: if x is not None and y is not None: # code here else: if x is None: # code here if y is None: # code here 有没有更好的方法来做到这一点？ 我正在寻找一个更短的IF ELSE结构。 保持您使用的订单： if x is None and y is None: # code here for
I'm doing this week's 'easy' Daily Programmer Challenge on Reddit. The description is at the link, but essentially the challenge is to read a text file from a url and do a word count. Needless to say the resulting output is a fairly large dictionary object. I have a few questions, mostly regarding accessing or sorting keys according to their value. First, I developed the code
我正在做这个星期在Reddit上的'简单'每日程序员挑战赛。 描述位于链接处，但本质上面临的挑战是从URL中读取文本文件并进行字数统计。 不用说，结果输出是一个相当大的字典对象。 我有几个问题，主要是根据它们的价值访问或分类键。 首先，我根据目前对面向对象和良好Python风格的理解开发了代码。 我希望它尽可能健壮，但我也想使用最少量的导入模块。 我的目标是成为一名优秀的程序员，因此我认为，建立一个坚实
Learning some python by reading some code and trying to understand the usage of None on the dictionary's. Could you please bring some more light on the following snippet. and the usage of the = None . for pc in csv_dict: if pc in shp_dict: matched[pc] = None else: csv_not_in_shp[pc] = None Thanks I think you're right to be confused, because th
通过阅读一些代码学习一些python并试图理解字典上的None的用法。 你能否在下面的片段中提供一些更多的信息。 和= None的用法。 for pc in csv_dict: if pc in shp_dict: matched[pc] = None else: csv_not_in_shp[pc] = None 谢谢 我认为你很困惑，因为这不会让我成为Python编码的最好例子。 只需查看标识符名称，我们就可以看到作者的意图： for pc in csv_dict: if pc in
Actually this is a Python in GIS, so I use table in my Arcgis and try to count the field and divided it by using category. I have Field named Elevation the data contain integer example : 1 - 2 3 - 6 2 - 3 8.5 - 12 11 - 12 I need to categorize it using rule that if Elevation < 1 then Index = 0.3 ,if Elevation = 2 - 3 Index = 0.6, if Elevation > 3 Index = 1 I have this code
实际上，这是一个GIS中的Python，所以我在Arcgis中使用了表格，并尝试对该字段进行计数并使用类别进行分割。 我有名为Elevation的字段数据包含整数示例： 1 - 2 3 - 6 2 - 3 8.5 - 12 11 - 12 我需要使用规则对它进行分类 如果高程<1，那么索引= 0.3，如果高程= 2 - 3索引= 0.6，如果高程> 3索引= 1 我有这样的代码： def Reclass( Elevation ): r_min, r_max = (float(s.strip()) fo
I'm writing a little function to return the index of the first occurrence of a string in a list of strings, using a "fuzzy" comparison. My question is: what is the proper way to signify the target string not matching any in the source list? The obvious (only?) thing to do is to return -1. But since -1 in Python means the last element of a sequence, it occurs to me this may not
我写了一个小函数来返回字符串列表中第一次出现字符串的索引，使用“模糊”比较。 我的问题是：什么是正确的方式来表示目标字符串不匹配任何在源列表中？ 显而易见的（只有？）要做的是返回-1。 但是由于Python中的-1意味着序列的最后一个元素，所以对我来说这可能不是很好的Python风格。 有更多Pythonic（Pythonesque？）方式吗？ 你可以返回None它是空对象。 要检查结果，您将使用is运算符。 在Python中检查空对象？
I have this class: class View(object): def main_page(self, extra_placeholders = None): file = '/media/Shared/sites/www/subdomains/pypular/static/layout.tmpl' placeholders = { 'site_name' : 'pypular' } # If we passed placeholders vars, append them if extra_placeholders != None: for k, v in extra_placeholders.iteritems(): placehol
我有这个班级： class View(object): def main_page(self, extra_placeholders = None): file = '/media/Shared/sites/www/subdomains/pypular/static/layout.tmpl' placeholders = { 'site_name' : 'pypular' } # If we passed placeholders vars, append them if extra_placeholders != None: for k, v in extra_placeholders.iteritems(): placeholders
{ "_id" : 160, "info" : [ { 'name': 'Serg', 'proff': 'hacker' }, null, ] } As you can see I have null element in my array, I need a general solution that will remove null elements from info array. I tried this: for doc in iter: people.update({ '_id' : doc['_id']}, { '$pull' : { 'info' : 'null' }
{ "_id" : 160, "info" : [ { 'name': 'Serg', 'proff': 'hacker' }, null, ] } 正如你所看到的，我的数组中有空元素，我需要一个通用的解决方案，它将从信息数组中删除空元素。 我试过这个： for doc in iter: people.update({ '_id' : doc['_id']}, { '$pull' : { 'info' : 'null' }}) 其中iter是文档的集合。 peo
I have a method that sometimes returns a NoneType value. So how can I question a variable that is a NoneType? I need to use if method, for example if not new: new = '#' I know that is the wrong way and I hope you understand what I meant. So how can I question a variable that is a NoneType? Use is operator, like this if variable is None: Why this works? Since None is the sole singl
我有一个方法有时返回一个NoneType值。 那么我怎么能问一个变量是一个NoneType？ 例如，我需要使用if方法 if not new: new = '#' 我知道这是错误的方式，我希望你明白我的意思。 那么我怎么能问一个变量是一个NoneType？ 使用is运营商，就像这样 if variable is None: 为什么这有效？ 由于None是Python中唯一的NoneType对象， NoneType我们可以使用is运算符来检查变量是否具有None 。 从报价is文档， 运算符
This question already has an answer here: null object in Python? 5 answers Change all nulls to None . In Python the 'null' object is the singleton None
这个问题在这里已经有了答案： Python中的空对象？ 5个答案 将所有空值更改为None 。 在Python中，'null'对象是单例None
I want to write a Django query equivalent to this SQL query: SELECT * from user where income >= 5000 or income is NULL. How to construct the Djagno queryset filter? User.objects.filter(income__gte=5000, income=0) This doesn't work, because it AND s the filters. I want to OR the filters to get union of individual querysets. from django.db.models import Q User.objects.filter(Q(income__
我想写一个相当于这个SQL查询的Django查询： SELECT * from user where income >= 5000 or income is NULL. 如何构建Djagno查询集过滤器？ User.objects.filter(income__gte=5000, income=0) 这是不行的，因为它AND S中的过滤器。 我想OR过滤器来获得单个查询集的联合。 from django.db.models import Q User.objects.filter(Q(income__gte=5000) | Q(income__isnull=True)) 通过文档 由于QuerySets实现了Python __or__