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Questions tagged [comparison]

Questions about data comparison and efficient ways to accomplish it. Please avoid using this tag for generic (meta) comparison of two issues or concepts.

Questions about data comparison and efficient ways to accomplish it, e.g.: "Which is the fastest algorithm to compare two recordsets and decide which one has more palindromes?", or "What is the fastest way to compare two strings and say if they have more than Y characters in common?"

There are generally six basic "comparison operators": less than, <; less than or equal to, <=; equal to, ==; not equal to, !=; greater than or equal to, >=; and greater than, >.

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Sort array of objects by string property value

I have an array of JavaScript objects: var objs = [ { first_nom: 'Lazslo', last_nom: 'Jamf' }, { first_nom: 'Pig', last_nom: 'Bodine' }, { first_nom: 'Pirate', last_nom: 'Prentice' } ]; How can I sort them by the value of…
Tyrone Slothrop
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Is there a standard function to check for null, undefined, or blank variables in JavaScript?

Is there a universal JavaScript function that checks that a variable has a value and ensures that it's not undefined or null? I've got this code, but I'm not sure if it covers all cases: function isEmpty(val){ return (val === undefined || val ==…
Alex
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Object comparison in JavaScript

What is the best way to compare objects in JavaScript? Example: var user1 = {name : "nerd", org: "dev"}; var user2 = {name : "nerd", org: "dev"}; var eq = user1 == user2; alert(eq); // gives false I know that two objects are equal if they refer to…
spankmaster79
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Why does comparing strings using either '==' or 'is' sometimes produce a different result?

Two string variables are set to the same value. s1 == s2 always returns True, but s1 is s2 sometimes returns False. If I open my Python interpreter and do the same is comparison, it succeeds: >>> s1 = 'text' >>> s2 = 'text' >>> s1 is s2 True Why is…
jottos
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In Bash, how can I check if a string begins with some value?

I would like to check if a string begins with "node" e.g. "node001". Something like if [ $HOST == node* ] then echo yes fi How can I do it correctly? I further need to combine expressions to check if HOST is either "user1" or begins with…
Tim
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How do I check for null values in JavaScript?

How can I check for null values in JavaScript? I wrote the code below but it didn't work. if (pass == null || cpass == null || email == null || cemail == null || user == null) { alert("fill all columns"); return false; } And…
Mahdi_Nine
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How to test multiple variables for equality against a single value?

I'm trying to make a function that will compare multiple variables to an integer and output a string of three letters. I was wondering if there was a way to translate this into Python. So say: x = 0 y = 1 z = 3 mylist = [] if x or y or z == 0: …
user1877442
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How do I do a case-insensitive string comparison?

How can I compare strings in a case insensitive way in Python? I would like to encapsulate comparison of a regular strings to a repository string, using simple and Pythonic code. I also would like to have ability to look up values in a dict hashed…
Kozyarchuk
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What is the Difference Between Mercurial and Git?

I've been using git for some time now on Windows (with msysGit) and I like the idea of distributed source control. Just recently I've been looking at Mercurial (hg) and it looks interesting. However, I can't wrap my head around the differences…
Spoike
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When to use CouchDB over MongoDB and vice versa

I am stuck between these two NoSQL databases. In my project, I will be creating a database within a database. For example, I need a solution to create dynamic tables. So users can create tables with columns and rows. I think either MongoDB or…
Luke101
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String comparison in Python: is vs. ==

I noticed a Python script I was writing was acting squirrelly, and traced it to an infinite loop, where the loop condition was while line is not ''. Running through it in the debugger, it turned out that line was in fact ''. When I changed it to…
Coquelicot
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What's the difference between equal?, eql?, ===, and ==?

I am trying to understand the difference between these four methods. I know by default that == calls the method equal? which returns true when both operands refer to exactly the same object. === by default also calls == which calls equal?... okay,…
denniss
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Check if all elements in a list are identical

I need a function which takes in a list and outputs True if all elements in the input list evaluate as equal to each other using the standard equality operator and False otherwise. I feel it would be best to iterate through the list comparing…
max
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544
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Compare two files in Visual Studio

I saw the new comparison tool in Visual Studio 2012 for comparing two files or two versions of a file. I like it. But when I tried to find it I couldn't it, because I don't use TFS. Is there a way how I can just compare two files with the built-in…
Libor Zapletal
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Comparing date part only without comparing time in JavaScript

What is wrong with the code below? Maybe it would be simpler to just compare date and not time. I am not sure how to do this either, and I searched, but I couldn't find my exact problem. BTW, when I display the two dates in an alert, they show as…
moleculezz
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