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Summarizing multiple columns with dplyr? [duplicate]
...brary(dplyr)
library(purrrlyr)
library(data.table)
library(bench)
set.seed(123)
n <- 10000
df <- data.frame(
a = sample(1:5, n, replace = TRUE),
b = sample(1:5, n, replace = TRUE),
c = sample(1:5, n, replace = TRUE),
d = sample(1:5, n, replace = TRUE),
grp = sample(1:3, n, replac...
Append to a file in Go
...
This answers works in Go1:
f, err := os.OpenFile(filename, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
if err != nil {
panic(err)
}
defer f.Close()
if _, err = f.WriteString(text); err != nil {
panic(err)
}
...
How to detect the OS from a Bash script?
...I can use them between all the computers I use. The problem is I have some OS specific aliases so I was looking for a way to determine if the script is running on Mac OS X, Linux or Cygwin .
...
Find all files in a directory with extension .txt in Python
...
You can use glob:
import glob, os
os.chdir("/mydir")
for file in glob.glob("*.txt"):
print(file)
or simply os.listdir:
import os
for file in os.listdir("/mydir"):
if file.endswith(".txt"):
print(os.path.join("/mydir", file))
or if you ...
Redirect stdout to a file in Python?
...pt on Windows using just script's name
– Piotr Dobrogost
Oct 4 '12 at 11:00
7
It doesn't work wit...
Does Python have “private” variables in classes?
...names the variable.
class A:
def __init__(self):
self.__var = 123
def printVar(self):
print self.__var
Now, if you try to access __var outside the class definition, it will fail:
>>>x = A()
>>>x.__var # this will return error: "A has no attribute __var...
Python: Get relative path from comparing two absolute paths
...
os.path.commonprefix() and os.path.relpath() are your friends:
>>> print os.path.commonprefix(['/usr/var/log', '/usr/var/security'])
'/usr/var'
>>> print os.path.commonprefix(['/tmp', '/usr/var']) # No com...
How can I create directories recursively? [duplicate]
...
os.makedirs is what you need. For chmod or chown you'll have to use os.walk and use it on every file/dir yourself.
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How do I check if I'm running on Windows in Python? [duplicate]
...e platform module but it says it returns 'Windows' and it's returning 'Microsoft' on my machine. I notice in another thread here on stackoverflow it returns 'Vista' sometimes.
...
Retrieving parameters from a URL
...
import urlparse
url = 'http://example.com/?q=abc&p=123'
par = urlparse.parse_qs(urlparse.urlparse(url).query)
print par['q'][0], par['p'][0]
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