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How can I filter lines on load in Pandas read_csv function?
...about memory running out, then use an iterator and apply the filter as you concatenate chunks of your file e.g.:
import pandas as pd
iter_csv = pd.read_csv('file.csv', iterator=True, chunksize=1000)
df = pd.concat([chunk[chunk['field'] > constant] for chunk in iter_csv])
You can vary the chunk...
Is it possible to dynamically compile and execute C# code fragments?
...bly. The analogy: I can create an HTML page using the DOM, or using string concats.
– Cheeso
May 14 '09 at 21:49
here'...
What is the difference between currying and partial application?
...m,_){1+accum})(empty-list);
function reverse = curry(fold)(lambda(accum,e){concat(e,accum)})(empty-list);
/* ... */
@list = [1, 2, 3, 4]
sum(list) //returns 10
@f = fold(lambda(accum,e){e+accum}) //f = lambda(accumulator,list) {/*...*/}
f(0,list) //returns 10
@g = f(0) //same as sum
g(list) //retu...
How to generate and validate a software license key?
...hen:
Generate yourself a secret key for the product
Take the user's name
Concatentate the users name and the secret key and hash with (for example) SHA1
Unpack the SHA1 hash as an alphanumeric string. This is the individual user's "Product Key"
Within the program, do the same hash, and compare wit...
Add spaces before Capital Letters
...here in one line with linq:
var val = "ThisIsAStringToTest";
val = string.Concat(val.Select(x => Char.IsUpper(x) ? " " + x : x.ToString())).TrimStart(' ');
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...
Any equivalent to .= for adding to beginning of string in PHP?
...n assignment operator and no one commented on its usage for general string concatenation.
You may want to look into the use of the sprintf (documentation) family of functions for string concatenation.
It provides a lot more sanitization and usability than just combining two strings with assignment ...
Join vs. sub-query
...tion level).
Nested sub-queries
SELECT moo, bar
FROM (
SELECT moo, CONCAT(roger, wilco) AS bar
FROM foo
GROUP BY moo
HAVING bar LIKE 'SpaceQ%'
) AS temp_foo
ORDER BY bar
You can nest sub-queries in multiple levels. This can help on huge datasets if you have to group o...
Algorithm to return all combinations of k elements from n
...
elements.Skip(i + 1).Combinations(k - 1).Select(c => (new[] {e}).Concat(c)));
}
Usage:
var result = Combinations(new[] { 1, 2, 3, 4, 5 }, 3);
Result:
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Entity framework linq query Include() multiple children entities
...clude(nameof(Employee)) In case one needs to go further down names have to concatent with nameof(Employee)+"."+nameof(Employee_Car)
– Karl
Jan 19 '18 at 9:18
...
Why isn't Python very good for functional programming? [closed]
...
return layer
Haskell:
grandKids generation kidsFunc val =
iterate (concatMap kidsFunc) [val] !! generation
The main difference here is that Haskell's standard library has useful functions for functional programming: in this case iterate, concat, and (!!)
...