block

Is it possible to declare a method with block as default value?

由 无人久伴 提交于 2020-08-07 07:48:46
问题 I want to write a method which takes a block and if no block given it should use a default block. So I want to have something like this: def say_hello(name, &block = ->(name) { puts "Hi, #{name}" }) # do something end But when I'm trying to do so I'm getting the syntax error. I know I can deal with my problem using block_given?. But I am interested in first approach. Am I missing something or this is just not possible? 回答1: Some answers suggest using block_given? , but since there is no

Is it possible to declare a method with block as default value?

由 蹲街弑〆低调 提交于 2020-08-07 07:48:32
问题 I want to write a method which takes a block and if no block given it should use a default block. So I want to have something like this: def say_hello(name, &block = ->(name) { puts "Hi, #{name}" }) # do something end But when I'm trying to do so I'm getting the syntax error. I know I can deal with my problem using block_given?. But I am interested in first approach. Am I missing something or this is just not possible? 回答1: Some answers suggest using block_given? , but since there is no

What does the |variable| syntax mean? [duplicate]

由 痞子三分冷 提交于 2020-07-16 07:59:28
问题 This question already has answers here : What are those pipe symbols for in Ruby? (7 answers) Closed 8 days ago . What is the | | around profile below called, what does it mean, and why it is after do ? I thought do is followed by a loop block or so. ticks = get_all[0...MAX].map do |profile| # ... end 回答1: it's like a foreach, so profile will be a different value in each of the functions calls, one function call per element in get_all. see this: my_array = [:uno, :dos, :tres] my_array.each do

Display html element based on product attribute set?

由 夙愿已清 提交于 2020-06-01 05:08:23
问题 I wish to display a static block on the product page if the product belongs to a certain Attribute Set. The idea is to have a block show on product pages if the page has an attribute set of "Rc" else do not show block. I have a custom theme I made and already have a block made and displayed on ALL product pages. I would only need the block showing on product pages with an attribute set of "Rc". I am unaware of the folder structure and/or if the following code is applicable to magento 2.3.

Display html element based on product attribute set?

由 こ雲淡風輕ζ 提交于 2020-06-01 05:07:32
问题 I wish to display a static block on the product page if the product belongs to a certain Attribute Set. The idea is to have a block show on product pages if the page has an attribute set of "Rc" else do not show block. I have a custom theme I made and already have a block made and displayed on ALL product pages. I would only need the block showing on product pages with an attribute set of "Rc". I am unaware of the folder structure and/or if the following code is applicable to magento 2.3.

Accessing a passed block in Ruby

由 ⅰ亾dé卋堺 提交于 2020-05-28 06:05:06
问题 I have a method that accepts a block, lets call it outer. It in turn calls a method that accepts another block, call it inner. What I would like to have happen is for outer to call inner, passing it a new block which calls the first block. Here's a concrete example: class Array def delete_if_index self.each_with_index { |element, i| ** A function that removes the element from the array if the block passed to delete_if_index is true } end end ['a','b','c','d'].delete_if_index { |i| i.even? } =

Accessing a passed block in Ruby

由 梦想的初衷 提交于 2020-05-28 06:04:35
问题 I have a method that accepts a block, lets call it outer. It in turn calls a method that accepts another block, call it inner. What I would like to have happen is for outer to call inner, passing it a new block which calls the first block. Here's a concrete example: class Array def delete_if_index self.each_with_index { |element, i| ** A function that removes the element from the array if the block passed to delete_if_index is true } end end ['a','b','c','d'].delete_if_index { |i| i.even? } =

Create clusters using correlation matrix in Python

由 蓝咒 提交于 2020-05-14 20:30:31
问题 all, I have a correlation matrix of 21 industry sectors. Now I want to split these 21 sectors into 4 or 5 groups, with sectors of similar behaviors grouped together. Can experts shed me some lights on how to do this in Python please? Thanks much in advance! 回答1: You might explore the use of Pandas DataFrame.corr and the scipy.cluster Hierarchical Clustering package import pandas as pd import scipy.cluster.hierarchy as spc df = pd.DataFrame(my_data) corr = df.corr().values pdist = spc.distance

Create clusters using correlation matrix in Python

由 一笑奈何 提交于 2020-05-14 20:27:05
问题 all, I have a correlation matrix of 21 industry sectors. Now I want to split these 21 sectors into 4 or 5 groups, with sectors of similar behaviors grouped together. Can experts shed me some lights on how to do this in Python please? Thanks much in advance! 回答1: You might explore the use of Pandas DataFrame.corr and the scipy.cluster Hierarchical Clustering package import pandas as pd import scipy.cluster.hierarchy as spc df = pd.DataFrame(my_data) corr = df.corr().values pdist = spc.distance

详解Objective-c Block应用

由 时光毁灭记忆、已成空白 提交于 2020-05-05 21:05:34
目前只有Mac 10.6 和iOS 4有支援。Block是由一堆可執行的程式組成，也可以稱做沒有名字的Function (Anonymous function) AD： 2014WOT全球软件技术峰会北京站 课程视频发布 详解 Objective-c block 应用是本文要介绍的内容，主要介绍的是 Objective-c block 应用，不多说，先来看详细内容。 Apple 在 C , Objective-C , C++ 加上 Block 這個延申用法。目前只有Mac 10.6 和iOS 4有支援。 Block 是由一堆可執行的程式組成，也可以稱做沒有名字的Function (Anonymous function)。如果是Mac 10.6 或 iOS 4.0 之前的平台可以利用 http://code.google.com/p/plblocks/ 這個project得以支援Block語法。 Apple有一個叫做GCD(Grand Central Dispach)的新功能，用在同步處理(concurrency)的環境下有更好的效率。Block語法產生的動機就是來自於GCD，用Block包好一個工作量交給GCD，GCD有一個宏觀的視野可以來分配CPU，GPU，Memory的來下最好的決定。 Block 簡介 Block其實行為和Function很像
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