I went to a certain company for an interview (I won’t mention the company name, but this set of questions may still be used). I did a set of questions in 30 minutes on site, and one of them was like this:
Required to write a function in js , for the incoming URL string in the following form, return the corresponding object.
For example:
If the string a='?name=zhiyelee&blog=www.tsnrose.com';
is returned, b={'name':'zhiyelee','blog':'www .tsnrose.com'}
Due to the relatively short time at that time, there were some problems with the implementation. After I came back, I thought about it and summarized it as follows:
I thought of two ideas, one is to use regular expressions Expression, the second is to use the split function of string.
1. Use regular expression processing
The first thing I thought of was to use regular expression processing. It may be that this is more challenging and the simplest to write. However, I doubted that the efficiency of this method would be It is less efficient than directly using string functions. We will verify this efficiency below~
The idea of this method is very simple, which is to use regular expressions to match a string of '***=###' each time, and then loop and finally remove them all.
The code is as follows
var getNRReg = function(str) {
var res = {};
var reg = /(w )=(w )/g;
while ((a = reg.exec(str))) {
res[a [1]] = a[2];
}
return res;
};
2. The idea of using string functions to process
is also relatively simple Conventional, but it is definitely more troublesome to write than using regular expressions.
My idea is to first use '&' to split the original string into multiple strings. The style of each string is like '***=###', and then apply split('=') to the string. . (This method does not use regular expressions, of course we can use regular split(/&|=/)
The code is as follows
var getNRSplit = function(str) {
var temp, res = {},
i, ret;
str = str.slice(1 );
temp = str.split('&');
for (i = 0; i < temp.length; i ) {
ret = temp[i].split('=' );
res[ret[0]] = ret[1];
}
return res;
}
Efficiency issues of these two methods
It is well known that the efficiency of regular expressions is a bit low, so I initially thought that the efficiency of the first solution must be lower than the efficiency of the second solution, so I measured it and found otherwise:
Time-consuming to execute 1,000,000 times Situation:
getNRReg execution takes 4399ms
getNRSplit execution takes 6116ms
View the complete source code: jsfiddle, you can test it by yourself~
ps:
Finally attached is a written test question from Sina Weibo 2011-06-15 for a front-end position at Beijing Post Information Conference:
Use regular expressions to delete characters that are adjacent and identical to a certain character. For example, the string "fdaffdaaklfjk" becomes "fdafdakljk" after processing.
For my answer see
jsfiddle