R语言如何批量下载图片

微信公众号选择封面时，由于我没有大量的图片，每次现去网上下载几张图片很麻烦，所以搜索网上教材，找到批量下载的代码，下面是步骤。

1.在图片网址，右键选择检查。

image-20191123213134175

2.选择检查后，页面会变成网页结构信息如下图。找到div class的代码，记录下=后面的内容，是media_list。放在下一步代码hrml_nodes函数里。

网页结构图

3.代码如下，需要更改的是：

• url后面的图片网址，是含有很多图片的那个页面的网址。
• html_nodes函数后面的div.后面的内容就是在上面网页结构图中找到的div class后面的内容。

url <- 'https://pixabay.com/images/search/?cat=education'
picture<- read_html(url)%>% html_nodes("div.media_list")%>%html_nodes("img")%>%html_attr("src")
head(picture,20)
 [1] "https://cdn.pixabay.com/photo/2019/11/19/22/24/watch-4638673__340.jpg"     
 [2] "https://cdn.pixabay.com/photo/2019/11/04/10/15/book-4600757__340.jpg"      
 [3] "https://cdn.pixabay.com/photo/2019/11/13/17/04/ringtones-4624296__340.jpg" 
 [4] "https://cdn.pixabay.com/photo/2019/09/30/14/29/books-4515917__340.jpg"     
 [5] "https://cdn.pixabay.com/photo/2019/11/21/23/55/dog-4643784__340.jpg"       
 [6] "https://cdn.pixabay.com/photo/2019/11/20/19/08/confused-4640878__340.jpg"  
 [7] "https://cdn.pixabay.com/photo/2019/11/03/16/29/woman-4599055__340.png"     
 [8] "https://cdn.pixabay.com/photo/2019/11/13/11/21/dog-4623296__340.jpg"       
 [9] "https://cdn.pixabay.com/photo/2019/11/17/16/57/statue-4632875__340.jpg"    
[10] "https://cdn.pixabay.com/photo/2019/11/08/12/33/book-4611273__340.jpg"      
[11] "https://cdn.pixabay.com/photo/2019/11/17/13/07/read-4632334__340.jpg"      
[12] "https://cdn.pixabay.com/photo/2017/03/07/13/02/thought-2123970__340.jpg"   
[13] "https://cdn.pixabay.com/photo/2019/09/28/12/36/auto-4510652__340.jpg"      
[14] "https://cdn.pixabay.com/photo/2019/11/11/07/38/office-4617459__340.png"    
[15] "https://cdn.pixabay.com/photo/2019/11/20/12/08/drawing-4639897__340.jpg"   
[16] "https://cdn.pixabay.com/photo/2019/08/14/18/51/school-bus-4406479__340.jpg"
[17] "/static/img/blank.gif"                                                     
[18] "/static/img/blank.gif"                                                     
[19] "/static/img/blank.gif"                                                     
[20] "/static/img/blank.gif"  
for(i in 1:length(picture)) 
{
  download(picture[i],paste("/Users/mengmeng/Downloads/脚本杂货铺/批量下载图片/批量下载图片1/picture",i,".jpg",sep = ""), mode = "wb")
} 

前面用head(picture,10)，下载下来图片只有16张，很是疑惑，于是head(picture,20)发现网址从16向后，确实都是无效网址了，但是我觉得代码没问题，我想应该是这个网址设置了保护（是国外的图片网址），不能批量下载，所以我又重新换了一个网址，依然右键检查，这次找到的div分区是<div class="indexpic">，如下图所示。

image-20191123211628031

代码如下

url <- 'https://www.quanjing.com/creative/' #换了另一个图片网址
picture<- read_html(url)%>% html_nodes("div.indexpic")%>%html_nodes("img")%>%html_attr("src")#更改的内容是indexpic

head(picture,51)
> head(picture,51)
 [1] "https://webimg.quanjing.com/creative/1.jpg"             "https://webimg.quanjing.com/creative/2.jpg"            
 [3] "https://webimg.quanjing.com/creative/3.jpg"             "https://webimg.quanjing.com/creative/4.jpg"            
 [5] "https://webimg.quanjing.com/creative/5.jpg"             "https://webimg.quanjing.com/creative/6.jpg"            
 [7] "https://webimg.quanjing.com/creative/7.jpg"             "https://webimg.quanjing.com/creative/8.jpg"            
 [9] "https://webimg.quanjing.com/creative/9.jpg"             "https://webimg.quanjing.com/creative/10.jpg"           
[11] "https://webimg.quanjing.com/creative/11.jpg"            "https://webimg.quanjing.com/creative/12.jpg"           
[13] "https://webimg.quanjing.com/creative/13.jpg"            "https://webimg.quanjing.com/creative/14.jpg"           
[15] "https://webimg.quanjing.com/creative/15.jpg"            "https://webimg.quanjing.com/creative/1547145496707.png"
[17] "https://webimg.quanjing.com/creative/1547146188597.jpg" "https://webimg.quanjing.com/creative/1547145999629.jpg"
[19] "https://webimg.quanjing.com/creative/24.jpg"            "https://webimg.quanjing.com/creative/25.jpg"           
[21] "https://webimg.quanjing.com/creative/26.jpg"            "https://webimg.quanjing.com/creative/2625120517.jpg"   
[23] "https://webimg.quanjing.com/creative/5625120517.jpg"    "https://webimg.quanjing.com/creative/2525120617.jpg"   
[25] "https://webimg.quanjing.com/creative/0203010610.jpg"    "https://webimg.quanjing.com/creative/0925120817.jpg"   
[27] "https://webimg.quanjing.com/creative/0003011510.jpg"    "https://webimg.quanjing.com/creative/2803011910.jpg"   
[29] "https://webimg.quanjing.com/creative/1203010810.jpg"    "https://webimg.quanjing.com/creative/0525121017.jpg"   
[31] "https://webimg.quanjing.com/creative/3125121017.jpg"    "https://webimg.quanjing.com/creative/3725121117.jpg"   
[33] "https://webimg.quanjing.com/creative/0525121217.jpg"    "https://webimg.quanjing.com/creative/0825121117.jpg"   
[35] "https://webimg.quanjing.com/creative/4525121217.jpg"    "https://webimg.quanjing.com/creative/1546619045476.png"
[37] "https://webimg.quanjing.com/creative/0625120417.jpg"    "https://webimg.quanjing.com/creative/1546618925012.png"
[39] "https://webimg.quanjing.com/creative/5525120217.jpg"    "https://webimg.quanjing.com/creative/2825120217.jpg"   
[41] "https://webimg.quanjing.com/creative/4003014609.jpg"    "https://webimg.quanjing.com/creative/3025123018.jpg"   
[43] "https://webimg.quanjing.com/creative/3425120918.jpg"    "https://webimg.quanjing.com/creative/0425121118.jpg"   
[45] "https://webimg.quanjing.com/creative/2425121318.jpg"    "https://webimg.quanjing.com/creative/1525121518.jpg"   
[47] "https://webimg.quanjing.com/creative/1425121718.jpg"    "https://webimg.quanjing.com/creative/5325121818.jpg"   
[49] "https://webimg.quanjing.com/creative/4925122218.jpg"    "https://webimg.quanjing.com/creative/2625122518.jpg"   
[51] "https://webimg.quanjing.com/creative/4925122718.jpg"   
for(i in 1:length(picture)) 
{
  download(picture[i],paste("/Users/mengmeng/Downloads/脚本杂货铺/批量下载图片/批量下载图片2/picture",i,".jpg",sep = ""), mode = "wb")
} 

gif2.gif

这次批量下载就全部成功了，picture总共有51，head(picture,51)，显示的网址也都是没问题的，最后成功下载51个。这里面只是把结果示例展示了出来，具体含义和为什么可以去看下面的参考哦。

参考：https://zhuanlan.zhihu.com/p/27649216

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