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How to get line count of a large file cheaply in Python?
...the entire file, figure out how many \n you have, and return that result.
Do you have a better way of doing that without reading the entire file? Not sure... The best solution will always be I/O-bound, best you can do is make sure you don't use unnecessary memory, but it looks like you have that co...
Passing a list of kwargs?
...s a list of kwargs to a method for brevity? This is what i'm attempting to do:
4 Answers
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How can I compare two lists in python and return matches
...
Not the most efficient one, but by far the most obvious way to do it is:
>>> a = [1, 2, 3, 4, 5]
>>> b = [9, 8, 7, 6, 5]
>>> set(a) & set(b)
{5}
if order is significant you can do it with list comprehensions like this:
>>> [i for i, j in zip(a,...
Serializing PHP object to JSON
...pelling reasons to stay at <5.4, or even already use version >= 5.4, do not use this answer, and just use PHP>= 5.4 (or, you know, a recent one) and implement the JsonSerializable interface
You would define a function, for instance named getJsonData();, which would return either an array...
Specifying column name in a “references” migration
...o make a migration in Rails, referencing another table. Usually, I would do something like:
6 Answers
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How to properly compare two Integers in Java?
... numeric promotion (JLS section 5.6.2). Look at each individual operator's documentation to see whether it's applied. For example, from the docs for == and != (JLS 15.21.1):
If the operands of an equality
operator are both of numeric type, or
one is of numeric type and the other
is convert...
Database, Table and Column Naming Conventions? [closed]
...ble as the entity, rather than the row in the table which the Plural crowd does. You have to ask your self which it is. If the table is just a container of rows, isn't it more logical to use plural naming? You would never name a collection in code singular, then why would you name the table singular...
When to use IMG vs. CSS background-image?
...th a z-index in order
to stretch a background image to fill its entire window.Note, this is no longer true with CSS3 background-size; see #6 below.
Using img instead of background-image can dramatically improve performance of animations over a background.
When to use CSS background-image
Use CS...
CSS3's border-radius property and border-collapse:collapse don't mix. How can I use border-radius to
...was that the td elements didn't also become rounded. You can solve that by doing something like this:
table tr:last-child td:first-child {
border-bottom-left-radius: 10px;
}
table tr:last-child td:last-child {
border-bottom-right-radius: 10px;
}
Now everything rounds properly, except tha...
Very large matrices using Python and NumPy
...of rows. It's also very fast; my 5 year old laptop can crunch through data doing SQL-like GROUP BY aggregation at 1,000,000 rows/second. Not bad for a Python-based solution!
Accessing the data as a NumPy recarray again is as simple as:
data = table[row_from:row_to]
The HDF library takes care of ...