How to go about removing the last element? For example, I have strings like these:
如何删除最后一个元素？例如，我有这样的字符串：
str1 = "My testing String"
str2 = "My another testing string"
I need a neat way of showing the output:
我需要一种简洁的方式来显示输出：
str1 = "My testing"
str2 = "My another testing"
This is what I could do:
这就是我能做的：
str1 = str1.split(" ")
str1.delete(str1.last)
str1.join(" ")
# => "My testing"
I was wondering if there's any neat way of doing this maybe in one line, like: str.split(" ", 2).last => "testing string", which should show "my testing" instead.
我想知道是否有任何简洁的方法可以在一行中执行此操作，例如：str.split（“”，2）.last =>“testing string”，它应显示“我的测试”。
EDIT
编辑
Thank you guys for the multiple and interesting answers. I appreciate your effort and time. But, I had to be fair, so I decided to benchmark everybody's answer. Here is the report with benchmark:
谢谢你们多个有趣的答案。我感谢你的努力和时间。但是，我必须公平，所以我决定对每个人的答案进行基准测试。以下是基准报告：
#!/usr/bin/ruby
require 'benchmark'
str2 = "My another testing string"
n = 500
Benchmark.bm(20) do |x|
x.report("str2[/(.*)\s/,1] "){ n.times { str2[/(.*)\s/,1] } }
x.report("str2[0...str2.rindex(' ')] "){ n.times { str2[0...str2.rindex(' ')] } }
x.report("str2.split(' ')[0...-1].join(' ') "){ n.times { str2.split(' ')[0...-1].join(' ') } }
x.report("str2[/.*(?=\s)/] "){ n.times { str2[/.*(?=\s)/] } }
end
user system total real
str2[/(.*) /,1] 0.000000 0.000000 0.000000 ( 0.001394)
str2[0...str2.rindex(' ')] 0.000000 0.000000 0.000000 ( 0.000956)
str2.split(' ')[0...-1].join(' ') 0.010000 0.000000 0.010000 ( 0.002569)
str2[/.*(?= )/] 0.000000 0.000000 0.000000 ( 0.001351)
Which makes it clear that answer p str2[0...str2.rindex(' ')] is performing well. Though I liked other approaches as well, very thoughtful and interesting. Thanks.
这清楚地表明答案p str2 [0 ... str2.rindex（''）]表现良好。虽然我也喜欢其他方法，但非常体贴和有趣。谢谢。
Second Edition
第二版
As per @theTineMan comment here is the updated benchmark:
根据@theTineMan的评论，这里是更新的基准：
require 'benchmark'
str2 = "My another testing string"
n = 999999
Benchmark.bmbm(20) do |x|
x.report("str2[/(.*)\s/,1] "){ n.times { str2[/(.*)\s/,1] } }
x.report("str2[0...str2.rindex(' ')] "){ n.times { str2[0...str2.rindex(' ')] } }
x.report("str2.split(' ')[0...-1].join(' ') "){ n.times { str2.split(' ')[0...-1].join(' ') } }
x.report("str2[/.*(?=\s)/] "){ n.times { str2[/.*(?=\s)/] } }
end
Rehearsal ----------------------------------------------------------------------
str2[/(.*) /,1] 1.030000 0.000000 1.030000 ( 1.033787)
str2[0...str2.rindex(' ')] 0.850000 0.000000 0.850000 ( 0.853124)
str2.split(' ')[0...-1].join(' ') 4.740000 0.000000 4.740000 ( 4.750215)
str2[/.*(?= )/] 0.990000 0.000000 0.990000 ( 0.990726)
------------------------------------------------------------- total: 7.610000sec
user system total real
str2[/(.*) /,1] 1.020000 0.000000 1.020000 ( 1.014772)
str2[0...str2.rindex(' ')] 0.830000 0.000000 0.830000 ( 0.839385)
str2.split(' ')[0...-1].join(' ') 4.620000 0.010000 4.630000 ( 4.629874)
str2[/.*(?= )/] 0.990000 0.000000 0.990000 ( 0.988224)
3 个解决方案
#1
11
str2 = "My another testing string"
p str2[/(.*)\s/,1] #=> My another testing
And if you are not a fan on regexp:
如果你不是regexp的粉丝：
str2 = "My another testing string"
p str2[0...str2.rindex(' ')] #=> My another testing
#2
9
With split you can slice the last array element like this:
使用split您可以像这样切片最后一个数组元素：
str1.split(' ')[0...-1].join(' ')
#3
7
str1[/.*(?=\s)/]
# => "My testing"
str2[/.*(?=\s)/]
# => "My another testing"
#1
11
str2 = "My another testing string"
p str2[/(.*)\s/,1] #=> My another testing
And if you are not a fan on regexp:
如果你不是regexp的粉丝：
str2 = "My another testing string"
p str2[0...str2.rindex(' ')] #=> My another testing
#2
9
With split you can slice the last array element like this:
使用split您可以像这样切片最后一个数组元素：
str1.split(' ')[0...-1].join(' ')
#3
7
str1[/.*(?=\s)/]
# => "My testing"
str2[/.*(?=\s)/]
# => "My another testing"