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Looking for a clear definition of what a “tokenizer”, “parser” and...

I am looking for a clear definition of what a "tokenizer", "parser" and "lexer" are and how they are related to each other (e.g., does a parser use a tokenizer or vice versa)? I need to create a program will go through c/h source files to extract data declaration and definitions. ...
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Python list subtraction operation

...set(x) - set(y)) >>> z [0, 8, 2, 4, 6] Or you might just have x and y be sets so you don't have to do any conversions. share | improve this answer | follow ...
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How does zip(*[iter(s)]*n) work in Python?

...unction call. Therefore you're passing the same iterator 3 times to zip(), and it pulls an item from the iterator each time. x = iter([1,2,3,4,5,6,7,8,9]) print zip(x, x, x) share | improve this a...
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Getting vertical gridlines to appear in line plot in matplotlib

I want to get both horizontal and vertical grid lines on my plot but only the horizontal grid lines are appearing by default. I am using a pandas.DataFrame from an sql query in python to generate a line plot with dates on the x-axis. I'm not sure why they do not appear on the dates and I have trie...
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Paperclip::Errors::MissingRequiredValidatorError with Rails 4

...ays "MissingRequiredValidatorError" I thought that by updating post_params and giving it :image it would be fine, as both create and update use post_params ...
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Matplotlib connect scatterplot points with line - Python

I have two lists, dates and values. I want to plot them using matplotlib. The following creates a scatter plot of my data. ...
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How to prove that a problem is NP complete?

...least one vertex in the cover set?) is in NP: our input X is some graph G and some number k (this is from the problem definition) Take our information C to be "any possible subset of vertices in graph G of size k" Then we can write an algorithm V that, given G, k and C, will return whether that s...
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iPhone - Get Position of UIView within entire UIWindow

...he coordinate system ist defined by the bounds of the window. The screen's and device coordinate systems are different and should not be mixed up with window coordinates. share | improve this answe...
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Showing data values on stacked bar chart in ggplot2

...sition = position_stack(vjust = 0.5)) Also note that "position_stack() and position_fill() now stack values in the reverse order of the grouping, which makes the default stack order match the legend." Answer valid for older versions of ggplot: Here is one approach, which calculates the midpo...
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JavaScript ternary operator example with functions

...else syntax because I don't like to sacrifice readability - I'm old-school and I prefer my braces. The full if/then/else format is used for pretty much everything. It's especially popular if you get into larger blocks of code in each branch, you have a muti-branched if/else tree, or multiple else/...