No error , No gain

I have a DataFrame from Pandas: import pandas as pd inp = [{'c1':10, 'c2':100}, {'c1':11,'c2':110}, {'c1':12,'c2':120}] df = pd.DataFrame(inp) print df Output: c1 c2 0 10 100 1 11 110 2 12 120 Now I want to iterate over the rows of this frame. For every row I want to be able to access its elements (values in cells) by the name of the columns. For example: for row in df.rows: print row['c1'], row..

What's the best way of checking if an object property in JavaScript is undefined? The usual way to check if the value of a property is the special value undefined, is: if(o.myProperty === undefined) { alert("myProperty value is the special value `undefined`"); } To check if an object does not actually have such a property, and will therefore return undefined by default when you try and access it..

How can I add a column with a default value to an existing table in SQL Server 2000 / SQL Server 2005? Syntax: ALTER TABLE {TABLENAME} ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE} WITH VALUES Example: ALTER TABLE SomeTable ADD SomeCol Bit NULL --Or NOT NULL. CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated. D..

There have been several questions already posted with specific questions about dependency injection, such as when to use it and what frameworks are there for it. However, What is dependency injection and when/why should or shouldn't it be used? The best definition I've found so far is one by James Shore: "Dependency Injection" is a 25-dollar term for a 5-cent concept. [...] Dependency injection ..

Can I convert a string representing a boolean value (e.g., 'true', 'false') into a intrinsic type in JavaScript? I have a hidden form in HTML that is updated based upon a user's selection within a list. This form contains some fields which represent boolean values and are dynamically populated with an intrinsic boolean value. However, once this value is placed into the hidden input field it beco..

I'm trying to iterate over the words of a string. The string can be assumed to be composed of words separated by whitespace. Note that I'm not interested in C string functions or that kind of character manipulation/access. Also, please give precedence to elegance over efficiency in your answer. The best solution I have right now is: #include #include #include using namespace std; int main() { st..

I have the following code in Ruby. I want to convert this code into JavaScript. What is the equivalent code in JS? text =

When I want to prevent other event handlers from executing after a certain event is fired, I can use one of two techniques. I'll use jQuery in the examples, but this applies to plain-JS as well: 1. event.preventDefault() $('a').click(function (e) { // custom handling here e.preventDefault(); }); 2. return false $('a').click(function () { // custom handling here return false; }); Is there any sig..

I have a JavaScript object like the following: var p = { "p1": "value1", "p2": "value2", "p3": "value3" }; Now I want to loop through all p elements (p1, p2, p3...) And get their keys and values. How can I do that? I can modify the JavaScript object if necessary. My ultimate goal is to loop through some key value pairs and if possible I want to avoid using eval. You can use the for-in loop as sh..

When I make changes to a file in Git, how can I commit only some of the changes? For example, how could I commit only 15 lines out of 30 lines that have been changed in a file? You can use git add --patch (or -p for short), and git will begin to break down your file into what it thinks are sensible "hunks" (portions of the file). It will then prompt you with this question: Stage this hunk [y,n,q..

In PHP, strings are concatenated together as follows: $foo = "Hello"; $foo .= " World"; Here, $foo becomes "Hello World". How is this accomplished in Bash? foo="Hello" foo="${foo} World" echo "${foo}" > Hello World In general to concatenate two variables you can just write them one after another: a='Hello' b='World' c="${a} ${b}" echo "${c}" > Hello World codaddict Bash also supports a += operat..

How can I convert a String to an int in Java? My String contains only numbers, and I want to return the number it represents. For example, given the string "1234" the result should be the number 1234. String myString = "1234"; int foo = Integer.parseInt(myString); If you look at the Java documentation you'll notice the "catch" is that this function can throw a NumberFormatException, which of cou..

How can I check the existence of an element in jQuery? The current code that I have is this: if ($(selector).length > 0) { // Do something } Is there a more elegant way to approach this? Perhaps a plugin or a function? In JavaScript, everything is 'truthy' or 'falsy', and for numbers 0 means false, everything else true. So you could write: if ($(selector).length) You don't need that >0 part. Tim..

I've been told by others that writing using namespace std; in code is wrong, and that I should use std::cout and std::cin directly instead. Why is using namespace std; considered a bad practice? Is it inefficient or does it risk declaring ambiguous variables (variables that share the same name as a function in std namespace)? Does it impact performance? This is not related to performance at all...

The Python documentation seems unclear about whether parameters are passed by reference or value, and the following code produces the unchanged value 'Original' class PassByReference: def __init__(self): self.variable = 'Original' self.change(self.variable) print(self.variable) def change(self, var): var = 'Changed' Is there something I can do to pass the variable by actual reference? Arguments ..

I'm trying to write a function that either accepts a list of strings, or a single string. If it's a string, then I want to convert it to an array with just the one item so I can loop over it without fear of an error. So how do I check if the variable is an array? The method given in the ECMAScript standard to find the class of Object is to use the toString method from Object.prototype. if(Object..

Say I'm in a Git repository. I delete a file and commit that change. I continue working and make some more commits. Then, I find I need to restore that file. I know I can checkout a file using git checkout HEAD^ foo.bar, but I don't really know when that file was deleted. What would be the quickest way to find the commit that deleted a given filename? What would be the easiest way to get that fi..

What does the explicit keyword mean in C++? The compiler is allowed to make one implicit conversion to resolve the parameters to a function. What this means is that the compiler can use constructors callable with a single parameter to convert from one type to another in order to get the right type for a parameter. Here's an example class with a constructor that can be used for implicit conversio..

What is the difference between __str__ and __repr__ in Python? Alex summarized well but, surprisingly, was too succinct. First, let me reiterate the main points in Alex’s post: The default implementation is useless (it’s hard to think of one which wouldn’t be, but yeah) __repr__ goal is to be unambiguous __str__ goal is to be readable Container’s __str__ uses contained objects’ __repr__ Default ..

I'm from a Subversion background and, when I had a branch, I knew what I was working on with "These working files point to this branch". But with Git I'm not sure when I am editing a file in NetBeans or Notepad++, whether it's tied to the master or another branch. There's no problem with git in bash, it tells me what I'm doing. To display the current branch you're on, without the other branches ..