Python Interviews: Difference between revisions

 
(9 intermediate revisions by the same user not shown)
Line 6:
 
= Open a file =
f = open('text.txt','r')
l = f.readlines()
f.close()
for i in l:
print(i.strip('\n'))
 
 
= Read Log File =
 
* Better way to open a file as it auto closed file, even on crash
<pre>
with open('/var/log/apache2/access.log','r') as file:
for line in file:
print(line.split()[3], line.split()[6], line.split()[8], line.split()[9])
try:
b = b +int(line.split()[9])
except:
pass
 
print(b)
</pre>
 
= List Comprehension =
Line 214 ⟶ 231:
 
= Justify Text =
 
[https://pyformat.info/ pyformat.info]
 
text.rjust(3,' ')
text.ljust(3,' ')
text.center(3,' ')
 
= Formatting =
[https://pyformat.info/ pyformat.info]
 
Old Method:
print('%s %s' % ('one','two'))
 
New Method:
print('{} {}'.format('one','two'))
 
Positional Index:
print('{1} {0}'.format(56,'ld'))
 
= Sorting =
 
listed ={}
 
plist = set(port_list)
listed.update({v:sorted(plist)})
 
for k,v in listed.items():
print("Tenant: ", k, "\nNo of Ports: ", len(v), '\n', [i for i in v if len(v) >0], '\n')
 
c = [1,5,2,3,9,6,2,0]
c.sort()
 
= Reverse a String =
'hello world'[::-1]
'dlrow olleh'
 
= Convert to Positive Number =
 
>>> a = -30
>>> abs(a)
30
 
* Interger can be positive or Negative:
>>> int(a)
-30
>>> -a
30
 
>>> c = 30.9
>>> int(c)
30
 
= "is" vs "==" =
 
a = [1,2,3]
b = a
 
c = [1,2,3]
 
print(a==c)
print(a is c)
 
Output:
True
False
 
 
= Dictionary =
 
a = {}