Python For Loop - Switching from PHP -

i new python , use php. can please clear me structure of loop python.

numbers = int(x) x in numbers 

in php realted loop used inside body. can't understand why methods before loop in python.

first of statement missing brackets:

numbers = [int(x) x in numbers] 

this called list comprehension , equivalent of:

numbers = [] x in numbers:    numbers.append(int(x)) 

note can use comprehensions generator expressions, in case [] become ():

numbers = (int(x) x in numbers) 

which equivalent of:

def numbers(n):    x in n:       yield int(x) 

this means loop execute 1 yield @ time being processed. in other words, while first example builds list in memory, generator returns 1 element @ time when executed. great process large lists can generate 1 element time without getting memory (e.g. processing file line-by-line).

so can see comprehensions , generator expressions great way reduce amount of code required process lists, tuples , other iterable.