Difference: 1. When printing, print() can only print one variable, while echo can print multiple variables; 2. "print_r()" will format the array or object and print it. out, and "var_dump()" will not only format the array or object, but also display the type.
The operating environment of this article: Windows 10 system, PHP version 7.1, Dell G3 computer.
1. Printing processing
print(); // 输出字符串 printf(); // 输出格式化字符串 print_r(); // 以易于理解的格式打印变量 echo; sprintf(); // 返回格式化字符串 var_dump(); // 打印变量的相关信息 var_export();// 输出或返回一个变量的字符串表示
2. Difference
1. The difference between print and echo
print and echo are both language structures;
print is printed time, only one variable can be printed, and echo can print multiple variables. If multiple variables are printed at the same time, separate them with commas, which is more efficient [recommended].
2. The difference between printf() and sprintf()
printf() can output according to the format and will be output directly to the buffer area;
sprintf() will return and will not output.
3. The difference between print_r() and var_dump()
print_r() will format the array/object and print it out [Help us troubleshoot Some errors or results];
var_dump() also has the function of print_r(), and var_dump() will also display the type of each one.
Fundamental difference:
For example: print FALSE, print_r() will have nothing, it is just equivalent to echoing a FALSE, nothing; if print_r() prints a TRUE, the result It is not true but 1, so there will be some errors in the judgment of some results, then [it is recommended to use var_dump()].
4. The difference between var_export and var_dump()
var_export() formats and outputs the content (such as an array). Of course, it can also be used later. The parameter is true, which will become a return;
For var_export(), the value it returns conforms to the syntax structure of PHP (such as a string that can be printed out as the syntax structure of PHP to use), but var_dump() cannot. var_dump() just helps us debug and check our error information or result information.
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