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Find integer index of rows with NaN in pandas dataframe
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And just in case, if you want to find the coordinates of 'nan' for all the columns instead (supposing they are all numericals), here you go:
df = pd.DataFrame([[0,1,3,4,np.nan,2],[3,5,6,np.nan,3,3]])
df
0 1 2 3 4 5
0 0 1 3 4.0 NaN 2
1 3 5 6 NaN 3.0 3
np.where(np.as...
Python - Count elements in list [duplicate]
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len(myList) should do it.
len works with all the collections, and strings too.
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When should you not use virtual destructors?
...o not declare a virtual destructor for a class? When should you specifically avoid writing one?
12 Answers
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Modulo operation with negative numbers
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C99 requires that when a/b is representable:
(a/b) * b + a%b shall equal a
This makes sense, logically. Right?
Let's see what this leads to:
Example A. 5/(-3) is -1
=> (-1) * (-3) + 5%(-3) = 5
This can only happen if 5%(-3) is 2.
Example B. (-5)/3 is -1
=> (-1) * 3 + (-5...
Selenium: FirefoxProfile exception Can't load the profile
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Update:
Selenium team fixed in latest version. For almost all environments the fix is:
pip install -U selenium
Unclear at which version it was fixed (apparently r13122), but certainly by 2.26.0 (current at time of update) it is fixed.
This error means that _wait_until_conn...
Real world use cases of bitwise operators [closed]
...checksums, parity, stop bits, flow control algorithms, and so on, which usually depend on the logic values of individual bytes as opposed to numeric values, since the medium may only be capable of transmitting one bit at a time.
Compression, Encryption
Both of these are heavily dependent on bitwise ...
How do I add the contents of an iterable to a set?
What is the "one [...] obvious way" to add all items of an iterable to an existing set ?
6 Answers
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Postgres - FATAL: database files are incompatible with server
...an run the below command to upgrade your postgres data directory retaining all data:
brew postgresql-upgrade-database
The above command is taken from the output of brew info postgres
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Dealing with commas in a CSV file
...any easily-available csv library - that is to say RFC 4180.
There's actually a spec for CSV format and how to handle commas:
Fields containing line breaks (CRLF), double quotes, and commas should be enclosed in double-quotes.
http://tools.ietf.org/html/rfc4180
So, to have values foo and ...
TypeScript sorting an array
..., b) {
var ax = [], bx = [];
a.replace(/(\d+)|(\D+)/g, function (_, $1, $2) { ax.push([$1 || Infinity, $2 || ""]) });
b.replace(/(\d+)|(\D+)/g, function (_, $1, $2) { bx.push([$1 || Infinity, $2 || ""]) });
while (ax.length && bx.length) {
var an = ax.shift();
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