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Creating a new column based on if-elif-else condition
...B'], 'C'] = 1
df.loc[df['A'] < df['B'], 'C'] = -1
Easy to solve using indexing. The first line of code reads like so, if column A is equal to column B then create and set column C equal to 0.
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Using DNS to redirect to another URL with a path [closed]
... subdomains, so instead of:
www.proof.com IN CNAME www.proof-two.com/path/index.htm
You could use:
www.proof.com IN CNAME proof.proof-two.com
then go to wherever you host proof-two.com and set it to point proof.proof-two.com to www.proof-two.com/path/index.htm.
~ there's always more than one wa...
Is there a good reason I see VARCHAR(255) used so often (as opposed to another length)?
...p being the effective maximum if you want to use UTF-8 and have the column indexed (because of index length limitations).
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String's Maximum length in Java - calling length() method
..., which is 2^31 - 1 (or approximately 2 billion.)
In terms of lengths and indexing of arrays, (such as char[], which is probably the way the internal data representation is implemented for Strings), Chapter 10: Arrays of The Java Language Specification, Java SE 7 Edition says the following:
The...
Algorithm to return all combinations of k elements from n
...hm 382: Combinations of M out of N Objects' (1970)
The algorithm in C...
Index of Combinations in Lexicographical Order (Buckles Algorithm 515)
You can also reference a combination by its index (in lexicographical order). Realizing that the index should be some amount of change from right to lef...
How to use ADB Shell when Multiple Devices are connected? Fails with “error: more than one device an
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Should be set ANDROID_SERIAL=7f1c864e, ie. without quotes.
– Bjonnfesk
Oct 8 '19 at 20:17
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How to represent empty char in Java Character class
... main(String[] args) throws Exception {
String s = "abcdefg";
int index = s.indexOf('d');
// delete a char from a char[]
char[] array = s.toCharArray();
char[] tmp = new char[array.length-1];
System.arraycopy(array, 0, tmp, 0, index);
System.arraycopy(array, index+1, tm...
schema builder laravel migrations unique on two columns
...
The second param is to manually set the name of the unique index. Use an array as the first param to create a unique key across multiple columns.
$table->unique(array('mytext', 'user_id'));
or (a little neater)
$table->unique(['mytext', 'user_id']);
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Git file permissions on Windows
...ing command adds user execute permission to an arbitrary file:
git update-index --chmod=+x <file>
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Pandas DataFrame Groupby two columns and get counts
...e your second question:
In [56]: df.groupby(['col5','col2']).size().reset_index().groupby('col2')[[0]].max()
Out[56]:
0
col2
A 3
B 2
C 1
D 3
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