正则表达式模式匹配串联

Question

I am trying to find some patterns of coding style in my solution. The use case is that I have to replace all the string concatenation with StringBuilder in razor and find all string concatenation in JavaScript . I am finding it very difficult to get all such code lines which have string concatenation in the following 2 ways.

1) str = str+str2+str3+"str4 " etc;
2) str+=str2+str3+"str4 " etc;

I tried using finding tool of VS 2013 and searched with character + , I got hell lot of lines. Please help me the reg ex pattern for above 2 styles of code lines, so at least number of lines will reduce. I am finding it difficult to get Reg Ex for above 2 styles of code.

Answer 1

([\w_]+[\w\d]*)(?:\s*=\s*\1{1}\s*\+\s*|\s*\+=\s*)("?[\w_]+[\w\d]*"?)(\s*\+\s*"?([\w_]+[\w\d]*"?))*;

Here I assumed that variable may start with an underline or a alphabetic character. You may want to make some changes to it if you need.

https://regex101.com/r/mE9zO7/2

Answer 2

也许是这样的：

(\w+ = \w+\+\w)|(\w+\s?\+=\s?\w+)

Answer 3

Keeping in mind the variable naming conventions that variable name can begin with an _ or [A-Za-z] this regex matches all such instances of concatenation.

Regex: ([A-Za-z_]\\w+)\\s*\\+?=\\s*(\\1\\s*)?(\\+?\\s*(([A-Za-z_]\\w+)|"?.*?"?))*;

Explanation:

• ([A-Za-z_]\\w+) matches the variable name starting with _ or [A-Za-z] followed by any character from word class.

• \\s*\\+? Optional whitespace and + to match shorthand concatenation operator .

• \\s*(\\1\\s*)? If shorthand operator is not used then this will match conventional way of concatenating.

• (\\+?\\s*(([A-Za-z_]\\w+)|"?.*?"?))* succeeding variable names which must be present. These could be zero or many . This could also be a literal string like "hello world" and also matches HTML data .

Regex101 Demo