检查python列表中的所有项目是否都包含子字符串

Question

I have a python list, that I am getting from api:

ERRATA_PKG_LIST = []
packages_key = "packages"
for pkgs, package_name in errata_rhel_ver_dic.iteritems():
    if pkgs == packages_key:
       ERRATA_PKG_LIST.append(package_name)
print(ERRATA_PKG_LIST)

Output:

[u'kernel-2.6.18-416.el5.i686',
 u'kernel-2.6.18-416.el5.x86_64',
 u'kernel-debug-2.6.18-416.el5.i686',
 u'kernel-debug-2.6.18-416.el5.x86_64',
 u'kernel-debug-devel-2.6.18-416.el5.i686',
 u'kernel-debug-devel-2.6.18-416.el5.x86_64',
 u'kernel-devel-2.6.18-416.el5.i686',
 u'kernel-devel-2.6.18-416.el5.x86_64',
 u'kernel-doc-2.6.18-416.el5.noarch',
 u'kernel-headers-2.6.18-416.el5.i386',
 u'kernel-headers-2.6.18-416.el5.x86_64',
 u'kernel-PAE-2.6.18-416.el5.i686',
 u'kernel-PAE-devel-2.6.18-416.el5.i686',
 u'kernel-xen-2.6.18-416.el5.i686',
 u'kernel-xen-2.6.18-416.el5.x86_64',
 u'kernel-xen-devel-2.6.18-416.el5.i686',
 u'kernel-xen-devel-2.6.18-416.el5.x86_64']

I want to check that each and every item in the list contains the substring: el5 if all of the objects in the list contains el5 ,then assign a variable rhel = "rhel 5" ,how do I achieve that ?

Answer 1

To test if every item matches a certain condition, try the builtin function all() along with a generator expression . In the generator expression, the test for substring containment is the in operator .

To filter a list, selecting only items which match some condition, use a list comprehension .

To print a list,the str.join() method is often useful.

ERRATA_PKG_LIST = [u'kernel-2.6.18-416.el5.i686', u'kernel-2.6.18-416.el5.x86_64', u'kernel-debug-2.6.18-416.el5.i686', u'kernel-debug-2.6.18-416.el5.x86_64', u'kernel-debug-devel-2.6.18-416.el5.i686', u'kernel-debug-devel-2.6.18-416.el5.x86_64', u'kernel-devel-2.6.18-416.el5.i686', u'kernel-devel-2.6.18-416.el5.x86_64', u'kernel-doc-2.6.18-416.el5.noarch', u'kernel-headers-2.6.18-416.el5.i386', u'kernel-headers-2.6.18-416.el5.x86_64', u'kernel-PAE-2.6.18-416.el5.i686', u'kernel-PAE-devel-2.6.18-416.el5.i686', u'kernel-xen-2.6.18-416.el5.i686', u'kernel-xen-2.6.18-416.el5.x86_64', u'kernel-xen-devel-2.6.18-416.el5.i686', u'kernel-xen-devel-2.6.18-416.el5.x86_64']


# To determine if 'el5' appears in every item
if all('el5' in item for item in ERRATA_PKG_LIST):
    rhel = "rhel 5"

# To generate the list of items which contain 'el5'
el5_list = [item for item in ERRATA_PKG_LIST if 'el5' in item]

# To generate the list of items which do NOT contain 'el5'
not_el5_list = [item for item in ERRATA_PKG_LIST if 'el5' not in item]

# To print a list:
print('\n'.join(el5_list))

Answer 2

if all(['el5' in item for item in ERRATA_PKG_LIST]):
    rhel = "rhel 5"

Answer 3

if all(map(lambda pkg: "el5" in pkg, ERRATA_PKG_LIST)):
        rhel = "rhel 5"

Answer 4

You could try using in .

def CheckList(list_items):
    for item in list_items:
        if 'el5' not in item:
            return False
    return True

This way you are going to loop through all elements of the list and check if the substring 'el5' is not in that item, if that evaluates true, your function returns False. Otherwise, it will end the loop and return True.