find files if directory name exists within directory in python

Question

I am trying to read some file which is inside some specific directory like. I am trying to use python2.7+ version. Here is my requirements like:

Find directory starts with B1234 (here 1234 is nr) inside output folder if directory exists then goto directories starting with only TEST_ read only file endswith YYYY.txt but that can reside inside subdirectory (name is not important here) I am trying to make following code working but in vain

for root, dirs, files in os.walk('output'):
    for file in files:
        if file.startswith('test') and file.endswith('_YYYY.txt'):
            try:
                f =  open(os.path.abspath(os.path.join(root,file)) , 'r')
            except:
                print 'oops'

Problem is here I can find all desired files but also from unwanted directories.. i would like to use like that

for dir in dirList:
if dir startswith(B1234)
for testdir in os.listdir(dir)
if dir.startswiht(TEST_)
goto dir
search for file

Any help will be appreciable..please askif you need more info:

Answer 1

I think you need to make the change here :

for root, dirs, files in os.walk('output'):
    for dir in dirs:
        if dir.startswith('B1234') is False:
            continue
        for r, drs, fls in os.walk(dir):
            # now write your code here