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When is it better to use String.Format vs string concatenation?
...rmance hit, but to be honest it'll be minimal if present at all - and this concatenation version doesn't need to parse the format string.
Format strings are great for purposes of localisation etc, but in a case like this concatenation is simpler and works just as well.
With C# 6
String interpolat...
Are there pronounceable names for common Haskell operators? [closed]
...lt;|> or / alternative expr <|> term: "expr or term"
++ concat / plus / append
[] empty list
: cons
:: of type / as f x :: Int: f x of type Int
\ lambda
@ as go ll@(l:ls): go ll as l cons ls
~ lazy go ~(a,b): go la...
Merge 2 arrays of objects
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same result as the much simpler: arr1 = arr1.concat(arr2)
– keithpjolley
Nov 1 '16 at 14:55
9
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How do I combine two data frames?
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You can also use pd.concat, which is particularly helpful when you are joining more than two dataframes:
bigdata = pd.concat([data1, data2], ignore_index=True, sort=False)
...
How do I kill all the processes in Mysql “show processlist”?
...n saves time. Do it in MySql itself:
Run these commands
mysql> select concat('KILL ',id,';') from information_schema.processlist
where user='root' and time > 200 into outfile '/tmp/a.txt';
mysql> source /tmp/a.txt;
Reference
---------edit------------
if you do not want to store in f...
Creating dataframe from a dictionary where entries have different lengths
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You can also use pd.concat along axis=1 with a list of pd.Series objects:
import pandas as pd, numpy as np
d = {'A': np.array([1,2]), 'B': np.array([1,2,3,4])}
res = pd.concat([pd.Series(v, name=k) for k, v in d.items()], axis=1)
print(res)
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Most efficient way to prepend a value to an array
...g an array to the front of another array, it is more efficient to just use concat. So:
var newArray = values.concat(oldArray);
But this will still be O(N) in the size of oldArray. Still, it is more efficient than manually iterating over oldArray. Also, depending on the details, it may help you, b...
How to remove element from array in forEach loop?
...se a string contains 'f', a result is different.
var review = ["of", "concat", "copyWithin", "entries", "every", "fill", "filter", "find", "findIndex", "flatMap", "flatten", "forEach", "includes", "indexOf", "join", "keys", "lastIndexOf", "map", "pop", "push", "reduce", "reduceRight", "reverse"...
How to get the difference between two arrays of objects in JavaScript
...er(comparer(b));
var onlyInB = b.filter(comparer(a));
result = onlyInA.concat(onlyInB);
console.log(result);
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Finding duplicate values in MySQL
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@NobleUplift You can do a GROUP_CONCAT(id) and it will list the IDs. See my answer for an example.
– Matt Rardon
Feb 19 '15 at 0:53
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