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What is the purpose of the word 'self'?
What is the purpose of the self word in Python? I understand it refers to the specific object created from that class, but I can't see why it explicitly needs to be added to every function as a parameter. To illustrate, in Ruby I can do this:
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Why doesn't print work in a lambda?
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A lambda's body has to be a single expression. In Python 2.x, print is a statement. However, in Python 3, print is a function (and a function application is an expression, so it will work in a lambda). You can (and should, for forward compatibility :) use the back-ported pri...
How to reference constants in EL?
...d Tomcat 8.0.2x+ works. And you need to make absolutely sure that your web.xml is declared conform the latest servlet version supported by the server. Thus with a web.xml which is declared conform Servlet 2.5 or older, none of the Servlet 3.0+ features will work.
Also note that this facility is onl...
Why does python use 'else' after for and while loops?
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It's a strange construct even to seasoned Python coders. When used in conjunction with for-loops it basically means "find some item in the iterable, else if none was found do ...". As in:
found_obj = None
for obj in objects:
if obj.key == search_key:
fou...
ValueError: numpy.dtype has the wrong size, try recompiling
I just installed pandas and statsmodels package on my python 2.7
When I tried "import pandas as pd", this error message comes out.
Can anyone help? Thanks!!!
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How do I pass extra arguments to a Python decorator?
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Converting HTML files to PDF [closed]
...eal problem with Flying Saucer is that it requires a well-formed and valid XML document. It's easy to unwittingly break the PDF rendering by including something like an ampersand in your HTML, or some javascript code that makes your rendered HTML not strict XHTML. Though this can be mitigated with a...
What is the EAFP principle in Python?
What is meant by "using the EAFP principle" in Python? Could you provide any examples?
3 Answers
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How to read the RGB value of a given pixel in Python?
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It's probably best to use the Python Image Library to do this which I'm afraid is a separate download.
The easiest way to do what you want is via the load() method on the Image object which returns a pixel access object which you can manipulate like an a...
When is “i += x” different from “i = i + x” in Python?
...lace_concat, and those C API functions have stricter requirements than the Python dunder methods, and… But I don't think that's relevant to the answer. The main distinction is that += tries to do an in-place add before falling back to acting like +, which I think you've already explained.
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