引号位于一行之上。它们应在句尾其他标点符号，如逗号（，），句号（。）之后。
The speech marks are above the line. They go outside all other marks like commas (, ) full stops (.).
这个转换器处理分组(如逗号)、小数、货币符号等。
This converter deals with grouping (such as commas), number of decimal digits, currency symbols, and such.
调用 preg_replace() 函数将用空字符串替换美元符号、所有空格和每个逗号，生成认为是整数的内容。
The call to the preg_replace() function replaces the dollar sign, any whitespace, and every comma with the empty string, yielding what's supposed to be an integer.
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