and-operator

Python's equivalent of && (logical-and) in an if-statement

由 纵饮孤独 提交于 2019-11-26 09:41:14
Here's my code: def front_back(a, b): # +++your code here+++ if len(a) % 2 == 0 && len(b) % 2 == 0: return a[:(len(a)/2)] + b[:(len(b)/2)] + a[(len(a)/2):] + b[(len(b)/2):] else: #todo! Not yet done. :P return I'm getting an error in the IF conditional. What am I doing wrong? You would want and instead of && . David Titarenco Python uses and and or conditionals. i.e. if foo == 'abc' and bar == 'bac' or zoo == '123': # do something Two comments: Use and and or for logical operations in Python. Use 4 spaces to indent instead of 2. You will thank yourself later because your code will look pretty

Regex AND operator

由 蓝咒 提交于 2019-11-26 04:46:45
问题 Based on this answer Regular Expressions: Is there an AND operator? I tried the following on http://regexpal.com/ but was unable to get it to work. What am missing? Does javascript not support it? Regex: (?=foo)(?=baz) String: foo,bar,baz 回答1: It is impossible for both (?=foo) and (?=baz) to match at the same time. It would require the next character to be both f and b simultaneously which is impossible. Perhaps you want this instead: (?=.*foo)(?=.*baz) This says that foo must appear anywhere

Javascript AND operator within assignment

由 为君一笑 提交于 2019-11-26 01:23:47
问题 I know that in JavaScript you can do: var oneOrTheOther = someOtherVar || \"these are not the droids you are looking for...\"; where the variable oneOrTheOther will take on the value of the first expression if it is not null , undefined , or false . In which case it gets assigned to the value of the second statement. However, what does the variable oneOrTheOther get assigned to when we use the logical AND operator? var oneOrTheOther = someOtherVar && \"some string\"; What would happen when

Python's equivalent of && (logical-and) in an if-statement

由 ￣綄美尐妖づ 提交于 2019-11-26 01:04:04
问题 Here\'s my code: def front_back(a, b): # +++your code here+++ if len(a) % 2 == 0 && len(b) % 2 == 0: return a[:(len(a)/2)] + b[:(len(b)/2)] + a[(len(a)/2):] + b[(len(b)/2):] else: #todo! Not yet done. :P return I\'m getting an error in the IF conditional. What am I doing wrong? 回答1: You would want and instead of && . 回答2: Python uses and and or conditionals. i.e. if foo == 'abc' and bar == 'bac' or zoo == '123': # do something 回答3: Two comments: Use and and or for logical operations in Python

How does C++ handle &&? (Short-circuit evaluation) [duplicate]

由 筅森魡賤 提交于 2019-11-26 00:24:10
问题 This question already has answers here : Is short-circuiting logical operators mandated? And evaluation order? (7 answers) Closed last year . When encountering a (bool1 && bool2), does c++ ever attempts to check bool2 if bool1 was found false or does it ignore it the way PHP does? Sorry if it is too basic of a question, but I really could not find a mentioning of that neither in Schildt nor on the Internet. 回答1: Yes, the && operator in C++ uses short-circuit evaluation so that if bool1

What is “x && foo()”?

由 十年热恋 提交于 2019-11-25 23:35:19
问题 I saw somewhere else said, x && foo(); 　is equal to if(x){ foo(); } I tested it and they really did the same thing. But why? What exactly is x && foo() ? 回答1: Both AND and OR operators can shortcut. So && only tries the second expression if the first is true (truth-like, more specifically). The fact that the second operation does stuff (whatever the contents of foo() does) doesn't matter because it's not executed unless that first expression evaluates to something truthy. If it is truthy, it

Boolean operators && and ||

由 大兔子大兔子 提交于 2019-11-25 22:26:18
问题 According to the R language definition, the difference between & and && (correspondingly | and || ) is that the former is vectorized while the latter is not. According to the help text, I read the difference akin to the difference between an \"And\" and \"AndAlso\" (correspondingly \"Or\" and \"OrElse\")... Meaning: That not all evaluations if they don\'t have to be (i.e. A or B or C is always true if A is true, so stop evaluating if A is true) Could someone shed light here? Also, is there an
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