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Search found 4503 results on 181 pages for 'logical operator'.

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  • Logical python question - handeling directories and files in them

    - by Konstantin
    Hello! I'm using this function to extract files from .zip archive and store it on the server: def unzip_file_into_dir(file, dir): import sys, zipfile, os, os.path os.makedirs(dir, 0777) zfobj = zipfile.ZipFile(file) for name in zfobj.namelist(): if name.endswith('/'): os.mkdir(os.path.join(dir, name)) else: outfile = open(os.path.join(dir, name), 'wb') outfile.write(zfobj.read(name)) outfile.close() And the usage: unzip_file_into_dir('/var/zips/somearchive.zip', '/var/www/extracted_zip') somearchive.zip have this structure: somearchive.zip 1.jpeg 2.jpeg another.jpeg or, somethimes, this one: somearchive.zip somedir/ 1.jpeg 2.jpeg another.jpeg Question is: how do I modify my function, so that my extracted_zip catalog would always contain just images, not images in another subdirectory, even if images are stored in somedir inside an archive.

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  • Boolean Not operator in VBScript

    - by Lumi
    Consider the following two conditionals (involving bitwise comparisons) in VBScript: If 1 And 3 Then WScript.Echo "yes" Else WScript.Echo "no" If Not(1 And 3) Then WScript.Echo "yes" Else WScript.Echo "no" Prints first yes, then no, right? cscript not.vbs Wrong! It prints yes twice! Wait a second, the Not operator is supposed to perform logical negation on an expression. The logical negation of true is false, as far as I know. Must I conclude that it doesn't live up to that promise? How and why and what is going on here? What is the rationale, if any?

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  • StringBuilder/StringBuffer vs. "+" Operator

    - by matt.seil
    I'm reading "Better, Faster, Lighter Java" (by Bruce Tate and Justin Gehtland) and am familiar with the readability requirements in agile type teams, such as what Robert Martin discusses in his clean coding books. On the team I'm on now, I've been told explicitly not to use the "+" operator because it creates extra (and unnecessary) string objects during runtime. But this article: http://www.ibm.com/developerworks/java/library/j-jtp01274.html Written back in '04 talks about how object allocation is about 10 machine instructions. (essentially free) It also talks about how the GC also helps to reduce costs in this environment. What is the actual performance tradeoffs between using "+," "StringBuilder," or "StringBuffer?" (In my case it is StringBuffer only as we are limited to Java 1.4.2.) StringBuffer to me results in ugly, less readable code, as a couple of examples in Tate's book demonstrates. And StringBuffer is thread-synchronized which seems to have its own costs that outweigh the "danger" in using the "+" operator. Thoughts/Opinions?

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  • What's the logical value of "string" in python?

    - by Kamran
    I erroneously wrote this code in python: name = input("what is your name?") if name == "Kamran" or "Samaneh": print("That is a nice name") else: print("You have a boring name ;)") It always prints out "That is a nice name" even when the input is neither "Kamran" nor "Samaneh". Am I correct in saying that it considers "Samaneh" as a true? why? By the way, I already noticed my mistake. The correct form is: if name == "Kamran" or name == "Samaneh":

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  • some logical error in taking up character in java

    - by Himanshu Aggarwal
    This is my code... class info{ public static void main (String[]args) throws IOException{ char gen; while(true) { //problem occurs with this while System.out.print("\nENTER YOUR GENDER (M/F) : "); gen=(char)System.in.read(); if(gen=='M' || gen=='F' || gen=='m' || gen=='f'){ break; } } System.out.println("\nGENDER = "+gen); } } This is my output... ENTER YOUR GENDER (M/F) : h ENTER YOUR GENDER (M/F) : ENTER YOUR GENDER (M/F) : ENTER YOUR GENDER (M/F) : m GENDER = m Could someone please help me understand why it is asking for the gender so many times.

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  • C: switch case with logical operator

    - by Er Avinash Singh
    While I am new to c and want help in this program my code is : #include<stdio.h> #include<conio.h> void main(){ int suite=2; switch(suite) { case 1||2: printf("hi"); case 3: printf("byee"); default: printf("hello"); } printf("I thought somebody"); getche(); } I am working in turbo c and it shows no error and the output is helloI thought somebody Please, let me know how is this working ??? note :- here break is not the case as I intentionally left them.

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  • override the operator overloading in C++ ?

    - by stdnoit
    helo guys i have class call Complex I did operator overloading like such Complex c = a + b; // where a and b are object of Complex class which basically is operator+(Complex& that); but I dont know how to say for example double c = a + 10; //where a is object of Complex class but 10 is integer / double I did define typecasting for a to be double get my IDE says that there are too many operands + and it somehow complains for not being able to "understand" the + it has to be in this format though double c = a + 10; thanks

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  • Lambda Functions in PHP aren't Logical

    - by Chacha102
    Note: I have condensed this article into my person wiki: http://wiki.chacha102.com/Lambda - Enjoy I am having some troubles with Lambda style functions in PHP. First, This Works: $foo = function(){ echo "bar"; }; $foo(); Second, This Works: class Bar{ public function foo(){ echo "Bar"; } Third, This works: $foo = new stdClass; $foo->bar = function(){ echo "bar"; }; $test = $foo->bar; $test(); But, this does not work: $foo = new stdClass; $foo->bar = function(){ echo "bar"; }; $foo->bar(); And, this does not work class Bar{ public function foo(){ echo "Bar"; } $foo = new Bar; $foo->foo = function(){ echo "foo"; }; $foo->foo(); // echo's bar instead of Foo. My Question is Why?, and how can I assure that both this: $foo->bar = function(){ echo "test"; }; $foo->bar(); and this $foo = new Bar; $foo->bar(); are called properly? Extra Points if you can point to documentation stating why this problem occurs.

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  • Operator + for matrices in C++

    - by cibercitizen1
    I suppose the naive implementation of a + operator for matrices (2D for instance) in C++ would be: class Matrix { Matrix operator+ (Matrix other) const { Matrix result; // fill result with *this.data plus other.data return result; } } so we could use it like Matrix a; Matrix b; Matrix c; c = a + b; Right? But if matrices are big this is not efficient as we are doing one not-necessary copy (return result). Therefore, If we wan't to be efficient we have to forget the clean call: c = a + b; Right? What would you suggest / prefer ? Thanks.

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  • boost::spirit::karma using the alternatives operator (|) with conditions

    - by Ingemar
    I'm trying to generate a string from my own class called Value using boost::spirit::karma, but i got stuck with this. I've tried to extract my problem into a simple example. I want to generate a String with karma from instances of the following class: class Value { public: enum ValueType { BoolType, NumericType }; Value(bool b) : type_(BoolType), value_(b) {} Value(const double d) : type_(NumericType), value_(d) {}; ValueType type() { return type_; } operator bool() { return boost::get<bool>(value_); } operator double() { return boost::get<double>(value_); } private: ValueType type_; boost::variant<bool, double> value_; }; Here you can see what I'm tying to do: int main() { using karma::bool_; using karma::double_; using karma::rule; using karma::eps; std::string generated; std::back_insert_iterator<std::string> sink(generated); rule<std::back_insert_iterator<std::string>, Value()> value_rule = bool_ | double_; Value bool_value = Value(true); Value double_value = Value(5.0); karma::generate(sink, value_rule, bool_value); std::cout << generated << "\n"; generated.clear(); karma::generate(sink, value_rule, double_value); std::cout << generated << "\n"; return 0; } The first call to karma::generate() works fine because the value is a bool and the first generator in my rule also "consumes" a bool. But the second karma::generate() fails with boost::bad_get because karma tries to eat a bool and calls therefore Value::operator bool(). My next thought was to modify my generator rule and use the eps() generator together with a condition but here i got stuck: value_rule = (eps( ... ) << bool_) | (eps( ... ) << double_); I'm unable to fill the brackets of the eps generator with sth. like this (of course not working): eps(value.type() == BoolType) I've tried to get into boost::phoenix, but my brain seems not to be ready for things like this. Please help me! here is my full example (compiling but not working): main.cpp

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  • has_many relation doesn't seems right or logical, some thing like belongs_to_many looks right

    - by Vijendra
    My situation is like this. Company has many users and users may belongs to many companies. And current implementation is something like below. class Company has_many :employments has_many :users, :through = :employments end class Employment belongs_to :company belongs_to :user end class User has_many :employments has_many :companies, :through = :employments #This doesn't looks correct end User has many companies doesn't looks logically meaningful.It must be some thing like belongs_to_many companies. Do I need to use has_and_belongs_to_many? But that also will gives the same meaning. Can some one please suggest the right way for representing these relationships?

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  • has_many relation doesn't seems right or logical in business perceptive, needed some thing like belo

    - by Vijendra
    My situation is like this. Company has many users and users may belongs to many companies. And current implementation is something like below. class Company has_many :employments has_many :users, :through = :employments end class Employment belongs_to :company belongs_to :user end class User has_many :employments has_many :companies, :through = :employments #This doesn't looks correct end It works, but "user has many companies" doesn't looks logically meaningful. It must be some thing like belongs_to_many companies. Do I need to use has_and_belongs_to_many? Can some one please suggest the right way for representing these relationships?

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  • Hex to bin after logical operations

    - by user355926
    I want: 111 || 100 ---> 111, not 1 100 && 100 ---> 100, not 1 101 && 010 ---> 000, not 0 Broken code #include <stdio.h> main(void){ string hexa = 0xff; strig hexa2 = 0xf1; // CONVERT TO INT??? cast int hexa3 = hexa || hexa2; int hexa4 = hexa && hexa2; puts(hexa3); puts(hexa4); }

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  • C++ conversion operator between types in other libraries

    - by Dave
    For convenience, I'd like to be able to cast between two types defined in other libraries. (Specifically, QString from the Qt library and UnicodeString from the ICU library.) Right now, I have created utility functions in a project namespace: namespace MyProject { const icu_44::UnicodeString ToUnicodeString(const QString& value); const QString ToQString(const icu_44::UnicodeString& value); } That's all well and good, but I'm wondering if there's a more elegant way. Ideally, I'd like to be able to convert between them using a cast operator. I do, however, want to retain the explicit nature of the conversion. An implicit conversion should not be possible. Is there a more elegant way to achieve this without modifying the source code of the libraries? Some operator overload syntax, perhaps?

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  • Logical Programming Problem

    - by user353060
    Hello, I've been trying to solve this problem for quite sometime but I am having trouble with it. Let's say on a trigger, you receive values. First trigger: You get 1 Second trigger: You get 1, 2 Third trigger: You get 1, 2, 3 So, I store 1. For 2nd trigger, I store 2 since 1 already exist. For 3rd trigger, I store 3 since 1,2 already exist so in total I have stored 1,2,3 As you can see, we can easily check for new values, if old != new. Here's come the problem: Fourth trigger: You get 1, 2, 4 For 4th trigger, I store 1, 2 because it exists but how do I check against 3 and remove 3 from store and check if 4 is new? If you are having problems understanding this, feel free to clarify. Thanks!

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  • Operator as and generic classes

    - by abatishchev
    I'm writing .NET On-the-Fly compiler for CLR scripting and want execution method make generic acceptable: object Execute() { return type.InvokeMember(..); } T Execute<T>() { return Execute() as T; /* doesn't work: The type parameter 'T' cannot be used with the 'as' operator because it does not have a class type constraint nor a 'class' constraint */ // also neither typeof(T) not T.GetType(), so on are possible return (T) Execute(); // ok } But I think operator as will be very useful: if result type isn't T method will return null, instead of an exception! Is it possible to do?

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  • A logical problem with two tables

    - by Luke
    Hey guys, I created a list for fixtures. $result = mysql_query("SELECT date FROM ".TBL_FIXTURES." WHERE compname = '$comp_name' GROUP BY date"); $i = 1; $d = "Start"; while ($row = mysql_fetch_assoc($result)) { $odate = $row['date']; $date=date("F j Y", $row['date']); echo "<p>Fixture $i - $d to $date</p>"; } As you can see from the query, the date is displayed from the fixtures table. The way my system works is that when a fixture is "played", it is removed from this table. Therefore when the entire round of fixtures are complete, there wont be any dates for that round in this table. They will be in another table. Is there anyway I can run an other query for dates at the same time, and display only dates from the fixtures table if there isnt a date in the results table? "SELECT * FROM ".TBL_CONF_RESULTS." WHERE compid = '$_GET[id]' && type2 = '2' ORDER BY date" That would be the second query!

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  • overloading new operator in c++

    - by Angus
    I have a code for best fit algorithm. I want to try to use the best fit algorithm using the operator new. Every time I create an object I should give it from the already allocated memory say, 1]20 2]12 3]15 4]6 5]23 respectively. which ever minimum amount fits to the objects size(eg.21) I wanted to do it for different object types, so I need to write the overloaded operator new to be common functionality for all the class objects. Can I do it through friend functions, or is there any possible way to do it.

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  • Turning logical expression around

    - by BluePrint
    I have the following code: bool s = true; for (...; ...; ...) { // code that defines A, B, C, D // and w, x, y, z if (!(A < w) && s == true) { s = false; } if (!(B < x) && s == true) { s = false; } if (!(C < y) && s == true) { s = false; } if (!(D < z) && s == true) { s = false; } } This code is working well. However, I want to, for several (unimportant) reasons, change the code so that I can initiate s = false; and set it to true inside the if-statement. It tried the following: bool s = false; for (...; ...; ...) { // code that defines A, B, C, D // and w, x, y, z if (A >= w && s == false) { s = true; } if (B >= x && s == false) { s = true; } if (C >= y && s == false) { s = true; } if (D >= z && s == false) { s = true; } } However, this is not working properly as the code above is working. I know thought wrong somewhere in the logic, but I can't figure out where. Does anbyone see my probably obvious error? EDIT: Added three more if-statemets. Missed them since they were commented away.

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  • SQL - logical AND among multiple rows

    - by potrnd
    Hello, First of all sorry that I could not think of a more descriptive title. What I want to do is the following using only SQL: I have some lists of strings, list1, list2 and list3. I have a dataset that contains two interesting columns, A and B. Column A contains a TransactionID and column B contains an ItemID. Naturally, there can be multiple rows that share the same TransactionIDs. I need to catch those transactions that have at least one item ID that exists whithin each list (list1, list2 AND list3). I also need to count how many times does that happen for each transaction. I hope that makes enough sense, perhaps I will be able to explain it better with a clear head. Thanks in advance

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