


In the previous article "How PHP uses functions to reverse numbers and print all palindrome numbers within a given range", we introduced how to determine the number of palindromes and use a for loop to output it to Method to find all palindromes within a certain range. This time we will learn about the multiplication table and see how to output the table using loop statements.
We have been exposed to the multiplication table since childhood and are very familiar with it. Therefore, printing the multiplication table is a programming problem that students who are just starting to program will definitely encounter. So how to implement it using PHP program? Let’s introduce it below.
First of all, let’s look at the multiplication table
We can get the pattern of the chart:
There are a total of 9 rows and 9 columns, and there are several expressions in each row.
In line
i
, the expression starts fromi*1
and ends ati*i
, There arei
expressions in total (we can achieve this effect through a loop).
Therefore, a double loop is needed to control the output. The outer loop controls the number of rows i (i is minimum 1 and the maximum is 9), and the inner loop controls column j (j is minimum 1, the maximum is equal to i). So using a for loop, you can write it like this:
for($i = 1; $i <= 9; $i++){ //外层循环控制行 for($j = 1; $j <= $i; $j++) //内层循环控制列 { } }
Now it’s time to write the program output part
echo "$j * $i = ".$i*$j." ";
Let’s take a look at the output result:
The multiplication expressions are all put together, which is not beautiful at all. It is different from the multiplication table at the beginning of the article. What is going on?
That’s because we are missing a line break step.
Based on the above program, we need to add a line break code in the outer loop to control the output of several expressions in each line.
"; } ?>
Let’s take a look at the output:
OK, is it very simple?
The above is implemented using a for loop, so how to implement it using a while loop? The following is my implementation method:
<?php $i=1; while($i<=9){ $j=1; while($j<=$i){ echo "$j x $i = ".$i*$j." "; $j++; } echo"<br/>"; $i++; } ?>
In fact, it is similar to a for loop. It also requires nesting two while loops. The outer while loop controls the number of rows, and the inner while loop controls the columns. [For those who don’t understand the while loop, you can read "PHP Loop Learning 1: Use of while loop statements (detailed examples)"]
to see the output results:
Okay, that’s all. If you want to know anything else, you can click this. → →php video tutorial
Recommended: 《PHP interview questions summary (collection)》
The above is the detailed content of PHP cycle learning seven: two methods of printing 9*9 quick calculation table. For more information, please follow other related articles on the PHP Chinese website!

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实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。


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