大约有 1,742 项符合查询结果（耗时：0.0171秒） [XML]
Fastest way to replace NAs in a large data.table
...) # v2.8.2
set.seed(1)
dt1 = create_dt(2e5, 200, 0.1)
dim(dt1)
[1] 200000 200 # more columns than Ramnath's answer which had 5 not 200
f_andrie = function(dt) remove_na(dt)
f_gdata = function(dt, un = 0) gdata::NAToUnknown(dt, un)
f_dowle = function(dt) { # see EDIT later for mor...
What is the most efficient way to create a dictionary of two pandas Dataframe columns?
...comparion (using Wouter's method)
In [6]: df = pd.DataFrame(randint(0,10,10000).reshape(5000,2),columns=list('AB'))
In [7]: %timeit dict(zip(df.A,df.B))
1000 loops, best of 3: 1.27 ms per loop
In [8]: %timeit pd.Series(df.A.values,index=df.B).to_dict()
1000 loops, best of 3: 987 us per loop
...
String output: format or concat in C#?
...ded the result by some iterations was wrong. See what happens if you have 1000 milliseconds and 100 milliseconds. In both situations, you will get 0 ms after dividing it by 1000000.
Stopwatch s = new Stopwatch();
var p = new { FirstName = "Bill", LastName = "Gates" };
int n = 1000000;
long fElaps...
Mediator Vs Observer Object-Oriented Design Patterns
....register(amb112);
operator.send(amb111, '27010 La Sierra Lane Austin, MN 000');
operator.unRegister(amb111);
operator.send(amb112, '97011 La Sierra Lane Austin, BN 111');
operator.unRegister(amb112);
The Differences:
The chat mediator has two way communication between the persons objects (sen...
C# switch statement limitations - why?
...le use if they aren't:
case 10: blah; break;
case 200: blah; break;
case 3000: blah; break;
(You'd need a table ~3000 entries in size, with only 3 slots used)
With non-adjacent expressions, the compiler may start to perform linear if-else-if-else checks.
With larger non- adjacent expression set...
Android studio, gradle and NDK
...on "19.0.2"
// This actual the app version code. Giving ourselves 100,000 values [0, 99999]
defaultConfig.versionCode = 123
flavorDimensions "api", "abi"
productFlavors {
gingerbread {
flavorDimension "api"
minSdkVersion 10
versionCode =...
Sleep Command in T-SQL?
... wait for a certain time...', 0, 1) WITH NOWAIT
WAITFOR TIME '16:43:30.000'
RAISERROR('I waited!', 0, 1) WITH NOWAIT
share
|
improve this answer
|
follow
...
Regular expression to match non-ASCII characters?
...(0-127, i.e. 0x0 to 0x7F).
You can do the same thing with Unicode:
[^\u0000-\u007F]+
For unicode you can look at this 2 resources:
Code charts list of Unicode ranges
This tool to create a regex filtered by Unicode block.
...
What is the best place for storing uploaded images, SQL database or disk file system? [closed]
... I had hit this problem before. NTFS behaved unpredictably with some 10,000 files in a folder.
– Faiz
Jun 20 '15 at 9:46
...
Reading a file line by line in Go
... ReadString/ReadBytes/... in bufio.Reader
In my testcase, ~250MB, ~2,500,000 lines, bufio.Scanner(time used: 0.395491384s) is faster than bufio.Reader.ReadString(time_used: 0.446867622s).
Source code: https://github.com/xpzouying/go-practice/tree/master/read_file_line_by_line
Read file use bufio...