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How to remove last n characters from every element in the R vector
...rame("data"=char_array,"data2"=1:4)
a$data = substr(a$data,1,nchar(a$data)-3)
a should now contain:
data data2
1 foo_ 1
2 bar_ 2
3 ap 3
4 b 4
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Getting the count of unique values in a column in bash
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153
To see a frequency count for column two (for example):
awk -F '\t' '{print $2}' * | sort | uniq...
How to write the Fibonacci Sequence?
... two numbers of the
sequence itself, yielding the sequence
0, 1, 1, 2, 3, 5, 8, etc.
If your language supports iterators you may do something like:
def F():
a,b = 0,1
while True:
yield a
a, b = b, a + b
Display startNumber to endNumber only from Fib sequence.
Once y...
How can I install an older version of a package via NuGet?
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edited Jun 25 at 6:36
Peter Mortensen
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Vagrant error : Failed to mount folders in Linux guest
I have some issues with Vagrant shared folders, my base system is Ubuntu 13.10 desktop.
21 Answers
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Interpolating a string into a regex
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answered Sep 29 '08 at 18:53
Jonathan LonowskiJonathan Lonowski
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Swift make method parameter mutable?
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As stated in other answers, as of Swift 3 placing var before a variable has been deprecated. Though not stated in other answers is the ability to declare an inout parameter. Think: passing in a pointer.
func reduceToZero(_ x: inout Int) {
while (x != 0) {
...
Adding a legend to PyPlot in Matplotlib in the simplest manner possible
...n call legend(loc='upper left').
Consider this sample (tested with Python 3.8.0):
import numpy as np
import matplotlib.pyplot as plt
x = np.linspace(0, 20, 1000)
y1 = np.sin(x)
y2 = np.cos(x)
plt.plot(x, y1, "-b", label="sine")
plt.plot(x, y2, "-r", label="cosine")
plt.legend(loc="upper left")
p...
Insert, on duplicate update in PostgreSQL?
... the_table (id, column_1, column_2)
VALUES (1, 'A', 'X'), (2, 'B', 'Y'), (3, 'C', 'Z')
ON CONFLICT (id) DO UPDATE
SET column_1 = excluded.column_1,
column_2 = excluded.column_2;
Searching postgresql's email group archives for "upsert" leads to finding an example of doing what you poss...