想要下载结肠癌的数据，原发位点为colon，按照老师的代码，报错，求老师指导
本想在老师帖子下边回复，可是评论不能分段，挤在一起太乱了。
以下是按老师代码简单改了改
resp = cases() %>% filter(~ project.project_id=='TCGA-COAD' &primary_site =='colon') %>% GenomicDataCommons::select(c(default_fields(cases()),'samples.sample_type')) %>% response_all()
resp %>% count()
[1] 454 ####我的网页数据是449，为什么这里是454？
case_name <- resp$results$submitter_id
download_name = substr(samplesDown,1,12)
####报错！Error in substr(samplesDown, 1, 12) : object 'samplesDown' not found
sample_download <- samplesDown[download_name %in% case_name]
######报错！Error: object 'samplesDown' not found
