# 1.1 環境安裝

因為我的電腦是MAC, 這邊就只記錄MAC的安裝方式. 至於Python版本, 這邊使用的是Python3.

**安裝 homebrew**:

參閱官網: <https://brew.sh/index_zh-tw.html>

**安裝 Python3:**

```bash
$ brew install python
$ brew install python3
```

Python 會被安裝在 **/usr/local/Cellar** 目錄之下

安裝好後, 你的 /usr/local/Cellar 目錄可能會長得類似這樣:

![](https://3902780279-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M523o3KiO0pmX6aiGw1%2F-M523rmaEjzd0w8x87jf%2F-M523sbj9fs_Uxyo_Qv_%2F1.1-1.png?generation=1587042036882849\&alt=media)

-> 注意python跟python3這兩個目錄.

**安裝virtualenv:**

虛擬環境的用意, 可以想成是一個沙盒, 不用擔心弄壞原本的環境, 也可以根據不同需求建立不同的虛擬環境.

```
$ pip install virtualenv
```

**建立一個virtual env:**

```
$ virtualenv -p python3 [env_name]
```

![](https://3902780279-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M523o3KiO0pmX6aiGw1%2F-M523rmaEjzd0w8x87jf%2F-M523sbl1_2wLhMmGMio%2F1.1-2.png?generation=1587042036373975\&alt=media)

建立好後, 來試著啟動虛擬環境吧:

```
$ source [env-name]/bin/activate
```

![](https://3902780279-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M523o3KiO0pmX6aiGw1%2F-M523rmaEjzd0w8x87jf%2F-M523sbnPctUcIMd-9rQ%2F1.1-3.png?generation=1587042037188193\&alt=media)

啟動成功的話, 可以在command line前面看到當前虛擬環境的名字(此處為web-crawler)

這時候查看一下python的版本, 會發現是python3:![](https://3902780279-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M523o3KiO0pmX6aiGw1%2F-M523rmaEjzd0w8x87jf%2F-M523sbpj-05AsxAIwhp%2F1.1-4.png?generation=1587042035865076\&alt=media)再來要安裝需要的套件, 如果你已經知道你要安裝什麼, 又懶得一個一個裝, 可以如下把所有要安裝的套件條列式的寫在一張[txt檔案](https://github.com/yotsuba1022/web-crawler-practice/blob/master/requirements.txt)裡面, 這邊我只列出這本gitbook裡面會需要用到的套件:

```
beautifulsoup4
requests
html5lib
matplotlib
selenium
jieba
wordcloud
Pillow==4.0.0
```

再來使用以下指令一次安裝所有套件:

```
$ pip install -r [txt_file_name]
```

安裝完後再確認一次:

```
$ pip list
```

![](https://3902780279-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M523o3KiO0pmX6aiGw1%2F-M523rmaEjzd0w8x87jf%2F-M523sbr4O4XUbZdOe_x%2F1.1-5.png?generation=1587042036164984\&alt=media)

這樣就安裝好虛擬環境了, 那麼要怎麼離開(deactivate)虛擬環境呢?

```
$ deactivate
```

![](https://3902780279-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M523o3KiO0pmX6aiGw1%2F-M523rmaEjzd0w8x87jf%2F-M523sbtmSQ1-SfYT4fr%2F1.1-6.png?generation=1587042036491559\&alt=media)

這樣就可以了, 很簡單吧\~

補充:

如果出現沒有切換至virtualenv就無法下python指令的情況, 在你的bash\_profile or bashrc裡面加入下面這項設定:

```
# DO NOT force vitualenv
export PIP_REQUIRE_VIRTUALENV=false
```


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