Hi all I would like to help me to do the following, I have following list :
prb = {{"https://www.youtube.com/watch?v=SGfM-JEEBvs"}, \
{"http://www.dma.fi.upm.es/docencia/segundociclo/geomfrac/proyectos/\
tutorial-mov-brow/Pagina%20Inicio.htm"}, \
{"http://tierrafertil.com.mx/otorgan-galardon-internacional-\
investigador-de-chapingo/"}, {"https://www.youtube.com/watch?v=KO3X7udtZKI"}, \
{"https://www.youtube.com/watch?v=2FhchwKHt00"}, \
{"https://www.youtube.com/watch?v=3lgh0RuJWnM"}, \
{"https://www.youtube.com/watch?v=Ct3dabOl9aA"}, \
{"https://www.youtube.com/watch?v=Hyc8XmRDwPY"}, \
{"http://community.wolfram.com/dashboard"}, \
{"http://blogsocl.com/segun-experto-asi-luce-el-cuerpo-\
cientificamente-perfecto-de-una-mujer-su-nombre-es-kelly-brook/#"}, , \
{"http://blog.linuxmint.com/"}, \
{"https://www.youtube.com/watch?v=5EpoIbj-i2o"}, \
{"https://www.youtube.com/watch?v=wZ969VcRTH0"}};
and I want to get in a single list all what start with "http://www.youtube something"
Thanks in advance, I hope that someone can help me because the original list contains about 300 elements too which complicates the task.