大约有 6,000 项符合查询结果（耗时：0.0333秒） [XML]
Why is a div with “display: table-cell;” not affected by margin?
...ss="table">
<div class="row">
<div class="cell">123</div>
<div class="cell">456</div>
<div class="cell">879</div>
</div>
</div>
CSS
.table {display:table;border-collapse:separate;border-spacing:5px;}
.row {di...
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...
Retrieving Android API version programmatically
...on, the SDK level (integer) the phone is running is available in:
android.os.Build.VERSION.SDK_INT
The class corresponding to this int is in the android.os.Build.VERSION_CODES class.
Code example:
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP){
// Do some...
Correct way to write line to file?
...le:
the_file.write('Hello\n')
From The Documentation:
Do not use os.linesep as a line terminator when writing files opened in text mode (the default); use a single '\n' instead, on all platforms.
Some useful reading:
The with statement
open()
'a' is for append, or use
'w' to write wi...
How do I change the working directory in Python?
...
You can change the working directory with:
import os
os.chdir(path)
There are two best practices to follow when using this method:
Catch the exception (WindowsError, OSError) on invalid path. If the exception is thrown, do not perform any recursive operations, especial...
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...
Deleting folders in python recursively
...o. As asked, the question was how to delete EMPTY directories.The docs for os.walk give an example that almost exactly matches this question: import os for root, dirs, files in os.walk(top, topdown=False): for name in dirs: os.rmdir(os.path.join(root, name))
...
How do I execute a program from Python? os.system fails due to spaces in path
...
Yes, the os.exec* functions will replace the current process, so your python process won't continue. They're used more on unix where the general method for a shell to launch a command is to fork() and then exec() in the child.
...
How to write log to file
...
os.Open() must have worked differently in the past, but this works for me:
f, err := os.OpenFile("testlogfile", os.O_RDWR | os.O_CREATE | os.O_APPEND, 0666)
if err != nil {
log.Fatalf("error opening file: %v", err)
}
def...
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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