Ruby StringScanner peek函数

StringScanner#peek() : peek()是StringScanner类的一个方法，它返回一个对应于string[pos, len]的字符串。

语法。StringScanner.peek()

参数。StringScanner值

len – 字符串值的长度

返回：与string[pos, len]相对应的一个字符串

例子 #1 :

# Ruby code for StringScanner.peek() method
  
# loading StringScanner
require 'strscan'
  
# declaring StringScanner 
c = StringScanner.new("Mon Sep 12 2018 14:39")
  
# peek() method
puts "String Scanner peek form : #{c.peek(3)}\n\n"
  
# peek() method
puts "String Scanner peek form : #{c.peek(6)}\n\n"
  
# peek() method
puts "String Scanner peek form : #{c.peek(9)}\n\n"

输出:

String Scanner peek form : Mon

String Scanner peek form : Mon Se

String Scanner peek form : Mon Sep 1

例子 #2 :

# Ruby code for StringScanner.peek() method
  
# loading StringScanner
require 'strscan'
  
# declaring StringScanner 
c = StringScanner.new("hellogeeks")
  
# peek() method
puts "String Scanner peek form : #{c.peek(2)}\n\n"
  
# peek() method
puts "String Scanner peek form : #{c.peek(4)}\n\n"
  
# peek() method
puts "String Scanner peek form : #{c.peek(8)}\n\n"

输出:

String Scanner peek form : he

String Scanner peek form : hell

String Scanner peek form : hellogee