ソフトウェアエンジニアの技術ブログ：Software engineer tech blog – Page 555 – 随机应变 ABCD: Always Be Coding and … : хороший

Groovy Closures

task groovy << {}

def foo = "One million dollars"
def myClosure = {
	println "Hello from a closure"
	println "The value of foo is $foo"
}

myClosure()

[vagrant@localhost ud867]$ gradle groovy
Hello from a closure
The value of foo is One million dollars
:groovy

BUILD SUCCESSFUL

Total time: 6.312 secs

task groovy << {}

def doubleIt = { x -> x + x}

def applyTwice(func, arg){
	func(func(arg))
}

def foo = 5
def fooDoubledTwice = applyTwice(doubleIt, foo)
println "Applying doubleIt twice to $foo equals $fooDoubledTwice"

[vagrant@localhost ud867]$ gradle groovy
Applying doubleIt twice to 5 equals 20
:groovy

BUILD SUCCESSFUL

Total time: 6.366 secs

task groovy << {}

def myList = ["Gradle", "Groovy", "Android"]

def printItem = {item -> println "List item: $item"}
myList.each(printItem)

super cool groovy

task groovy << {}

def noArgs(){
	println "Called the no args function"
}

def oneArg(x) {
	println "Called the 1 arg function with $x"
	x
}

def twoArgs(x, y){
	println "Called the  2 arg function with $x and $y"
	x + y
}

oneArg 500

[vagrant@localhost ud867]$ gradle groovy
Called the 1 arg function with 500
:groovy

BUILD SUCCESSFUL

Total time: 7.983 secs

Hey, what?

task groovy << {}

def noArgs(){
	println "Called the no args function"
}

def oneArg(x) {
	println "Called the 1 arg function with $x"
	x
}

def twoArgs(x, y){
	println "Called the  2 arg function with $x and $y"
	x + y
}

twoArgs 200, 300

[vagrant@localhost ud867]$ gradle groovy
Called the  2 arg function with 200 and 300
:groovy

BUILD SUCCESSFUL

Total time: 6.671 secs

task groovy << {}

def noArgs(){
	println "Called the no args function"
}

def oneArg(x) {
	println "Called the 1 arg function with $x"
	x
}

def twoArgs(x, y){
	println "Called the  2 arg function with $x and $y"
	x + y
}

twoArgs oneArg(500), 100

[vagrant@localhost ud867]$ gradle groovy
Called the 1 arg function with 500
Called the  2 arg function with 500 and 100
:groovy

BUILD SUCCESSFUL

Total time: 6.277 secs

groovy groovy groovy

task groovy << {}

def foo = 6.5

println "foo has value. $foo"
println "Let's do same math. 5 + 6 = ${5 + 6}"
println "foo is of type: ${foo.class} and has value: $foo"

foo = "a string"
println "foo is new of type: ${foo.class} and has value: $foo"

[vagrant@localhost ud867]$ gradle groovy
Hello Java!
:groovy

BUILD SUCCESSFUL

Total time: 6.464 secs
[vagrant@localhost ud867]$ gradle groovy
foo has value. 6.5
Let's do same math. 5 + 6 = 11
foo is of type: class java.math.BigDecimal and has value: 6.5
foo is new of type: class java.lang.String and has value: a string
:groovy

BUILD SUCCESSFUL

Total time: 6.531 secs

task groovy << {}

def doubleIt(n){
	n + n // Note we don't need a return statement
}

def foo = 5
println "doubleIt($foo) = ${doubleIt(foo)}"

foo = "foobar"
println "doubleIt($foo) = ${doubleIt(foo)}"

[vagrant@localhost ud867]$ gradle groovy
doubleIt(5) = 10
doubleIt(foobar) = foobarfoobar
:groovy

BUILD SUCCESSFUL

Total time: 6.396 secs

Groovy Fundamentals

build.gradle

task groovy << {}

[vagrant@localhost ud867]$ gradle groovy
:groovy

BUILD SUCCESSFUL

Total time: 9.107 secs

task groovy << {}

println "Hello Groovy!"

task groovy << {}

class JavaGreeter {
	public static void sayHello(){
		System.out.println("Hello Java!");
	}
}

JavaGreeter greeter = new JavaGreeter()
greeter.sayHello()

Gradle Daemon

[root@localhost src]# gradle --stop
No Gradle daemons are running.
[root@localhost src]# gradle hello World
Starting a Gradle Daemon (subsequent builds will be faster)

FAILURE: Build failed with an exception.

* What went wrong:
Task 'hello' not found in root project 'src'. Some candidates are: 'help'.

* Try:
Run gradle tasks to get a list of available tasks. Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 7.419 secs
[root@localhost src]# gradle hello World

FAILURE: Build failed with an exception.

* What went wrong:
Task 'hello' not found in root project 'src'. Some candidates are: 'help'.

* Try:
Run gradle tasks to get a list of available tasks. Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 1.66 secs

install gradle into CentOS

[root@localhost ~]# cd /usr/local/src/
[root@localhost src]# wget https://services.gradle.org/distributions/gradle-3.1-all.zip
[root@localhost src]# unzip gradle-3.1-all.zip 
[root@localhost src]# mv gradle-3.1 /usr/local/bin/

環境パスを追加

[root@localhost src]# vi ~/.bash_profile

export PATH=$PATH:/usr/local/bin/gradle-3.1/bin

反映

export PATH=$PATH:/usr/local/bin/gradle-3.1/bin

バージョン確認

[root@localhost src]# gradle -v

------------------------------------------------------------
Gradle 3.1
------------------------------------------------------------

Build time:   2016-09-19 10:53:53 UTC
Revision:     13f38ba699afd86d7cdc4ed8fd7dd3960c0b1f97

Groovy:       2.4.7
Ant:          Apache Ant(TM) version 1.9.6 compiled on June 29 2015
JVM:          1.8.0_111 (Oracle Corporation 25.111-b15)
OS:           Linux 2.6.32-642.6.2.el6.x86_64 amd64

Try gradle

git clone and run shell script

[vagrant@localhost 1.01-Exercise-RunYourFirstTask]$ ./gradlew hello
Downloading https://services.gradle.org/distributions/gradle-3.3-bin.zip
..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
Unzipping /home/vagrant/.gradle/wrapper/dists/gradle-3.3-bin/64bhckfm0iuu9gap9hg3r7ev2/gradle-3.3-bin.zip to /home/vagrant/.gradle/wrapper/dists/gradle-3.3-bin/64bhckfm0iuu9gap9hg3r7ev2
Set executable permissions for: /home/vagrant/.gradle/wrapper/dists/gradle-3.3-bin/64bhckfm0iuu9gap9hg3r7ev2/gradle-3.3/bin/gradle
Starting a Gradle Daemon (subsequent builds will be faster)
:hello
Hello World!

BUILD SUCCESSFUL

Total time: 1 mins 7.442 secs

task hello {
    doLast {
        println "Hello, Jeremy"
    }
}

Code snipet

if(chat.getAuthor().getAvatarId() == 0){
	
	Picasso.with(getContext()).load(android.R.color.transparent).into(chat_author_avatar);
		chat_author_avatar.setBackgroundColor(chat.getAuthor().getColor());
} else {
	Picasso.with(getContext()).load(chat.getAuthor().getAvatarId()).into(
		chat_author_avatar);
	chat_author_avatar.setBackgroundColor(Color.TRANSPARENT);
}

public int compute Fibonacci(int positionInFibSequence)
{
if (positionInFibSequence <= 2){ return 1; } else { return computeFibonacci(positionInFibSequence -1) + computeFibonacci(positionInFibSequence -2) } }[/python] [python] private class SepiaFilterTask extends AsyncTask { protected Bitmap doInBackground(Bitmap... bitmaps){ Bitmap loadedBitmap = bitmaps[0]; } sepiaBitmap.setPixel(x, y, Color.argb(alpha, outRed, outGreen, outBlue)); } } return sepiaBitmap; }[/python]

Optimizer

an optimizer
– find minimum values of functions
– build parameterized models based on data
– refine allocations to stocks in portfolios
f(x) = x^2 + x^3 + s
f(x) = (x-1.5)^2 + 0.5

"""Minimize an objective function, using SciPy."""

import pandas as pd
import matplotlib.pyplot as plt
import numpy as np
import scipy.optimize as spo

def f(X):
	"""Given a scalar X, return some value (a real number)."""
	Y = (X - 1.5)**2 + 0.5
	print "X = {}, Y = {}".format(X, Y)
	return Y

def test_run():
	Xguess = 2.0
	min_result = spo.minimize(f, Xguess, method='SLSQP', options={'disp': True})
	print "Minima found at:"
	print "X = {}, Y = {}".format(min_result.x, min_result.fun)

if __name__ == "__main__":
	test_run()

Pandas Fillna()

Pandas Fillna() documentation
http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.fillna.html
DataFrame.fillna(value=None, method=None, axis=None, inplace=False, limit=None, downcast=None, **kwargs)

fillna(method='ffill')

"""Plot a histogram"""

import pandas as pd
import matplotlib.pyplot as plt

from util import get_data, plot_data

def compute_daily_returns(df):
	daily_returns = df.copy()
	daily_returns[1:] = (df[1:] / df[:-1].values) - 1
	daily_returns.ix[0, :] = 0
	return daily_returns

def test_run():
	dates = pd.date_range('2009-01-01','2012-12-31')
	symbols = ['SPY']
	df = get_data(symbols, dates)
	plot_data(df)

	daily_returns - compute_daily_returns(df)
	plot_data(daily_returns, title="Daily returns", ylabel="Daily returns")

if __name__ == "__main__":
	test_run()

scatterplots in python

"""Scatterplot."""

import pandas as pd
import matplotlib.pyplot as plt

from util import get_data, plot_data

def compute_daily_returns(df):
	daily_returns = df.copy()
	daily_returns[1:] = (df[1:] / df[:-1].values) - 1
	daily_returns.ix[0, :] = 0
	return daily_returns

def test_run():
	dates = pd.date_range('2009-01-01', '2012-12-31')
	symbols = ['SPY', 'XOM', 'GLD']
	df = get_data(symbols, dates)
	
	daily_returns = compute_daily_returns(df)

	daily_returns.plot(kind='scatter',x='SPY',y='XOM')
	plt.show()

if __name__ == "__main__":
	test_run()