---
# System prepended metadata

title: Python Challenge Day 4 - Power

---

---
title: 'Python Challenge Day 4 - Power'
disqus: hackmd
---


## Python Challenge Day 4 - Power
### DESCRIPTION

The goal is to create a function of two inputs number and power, that "raises" the number up to power (ie multiplies number by itself power times).

### Examples:
```gherkin=
numberToPower(3, 2)  // -> 9 ( = 3 * 3 )
numberToPower(2, 3)  // -> 8 ( = 2 * 2 * 2 )
numberToPower(10, 6) // -> 1000000
```
### Note: 
Math.pow and some other Math functions like eval() and ** are disabled.



程式邏輯
---
目的：給兩個input（number,power），得出number的power次方。
例外：不能使用Math.pow，也不能使用eval()與**
1. 當power等於0，number的0次方為1，所以先給定一個值為1（test=1）
2. 用for迴圈執行條件式（test = test * number），執行次數為power的值


Solution
---
``` python
def number_to_pwr(number, p): 
    test = 1
    for i in range(p):
        test = test * number
    return test
```

* 使用 def 關鍵字來定義函數（number_to_pwr)
* [test *= number] = [test = test * number]
* 如果p=3，for迴圈會執行四次（0,1,2,3），當number=3會回傳如下：
第0次, test=1 * 3, test=3
第1次, test=3 * 3, test=9
第2次, test=9 * 3, test=27
第3次, test=27 *3 , test=81



## 參考資源

:::info
* [Kata](https://www.codewars.com/kata/562926c855ca9fdc4800005b)
:::

