Is a function in a for loop declaration will be called for many times in Python?
There is a function and a for loop:
def helper():
return [1,2,3]
for i in helper():
print(i)
I am wondering if the helper function would only be called once at the initialization of the for loop. As I am thinking that if I call the function and assign the return array to a variable in advance, which would be used in the for loop like this:
def helper():
return [1,2,3]
temp = helper()
for i in temp:
print(i)
Is that with less time complexity?
Thanks!
python for-loop time-complexity
asked Nov 25 '18 at 21:32
AuroraAurora
1098
add a comment |
There is a function and a for loop:
def helper():
return [1,2,3]
for i in helper():
print(i)
I am wondering if the helper function would only be called once at the initialization of the for loop. As I am thinking that if I call the function and assign the return array to a variable in advance, which would be used in the for loop like this:
def helper():
return [1,2,3]
temp = helper()
for i in temp:
print(i)
Is that with less time complexity?
Thanks!
python for-loop time-complexity
asked Nov 25 '18 at 21:32
AuroraAurora
1098
3
No, that is pretty much the same thing, except your first example doesn't need the temp variable so looks cleaner, easier to read etc. If you are ever unsure about things like this, just put print statements in your code to see what's happening.
– SuperShoot
Nov 25 '18 at 21:34
2
It is only evaluated once
– juanpa.arrivillaga
Nov 25 '18 at 21:35
3
You could test this yourself by printing a message inhelper(), and seeing if that message gets printed once, or more than once.
– John Gordon
Nov 25 '18 at 21:37
Got it, thanks!
– Aurora
Nov 25 '18 at 21:42
Yeah, adding some so-simple-it’s-a-no-brainerprintstatements is all you need to go fromwonderingToknowing
– barny
Nov 25 '18 at 21:57
add a comment |
There is a function and a for loop:
def helper():
return [1,2,3]
for i in helper():
print(i)
I am wondering if the helper function would only be called once at the initialization of the for loop. As I am thinking that if I call the function and assign the return array to a variable in advance, which would be used in the for loop like this:
def helper():
return [1,2,3]
temp = helper()
for i in temp:
print(i)
Is that with less time complexity?
Thanks!
python for-loop time-complexity
asked Nov 25 '18 at 21:32
AuroraAurora
1098
There is a function and a for loop:
def helper():
return [1,2,3]
for i in helper():
print(i)
I am wondering if the helper function would only be called once at the initialization of the for loop. As I am thinking that if I call the function and assign the return array to a variable in advance, which would be used in the for loop like this:
def helper():
return [1,2,3]
temp = helper()
for i in temp:
print(i)
Is that with less time complexity?
Thanks!
python for-loop time-complexity
python for-loop time-complexity
asked Nov 25 '18 at 21:32
AuroraAurora
1098
asked Nov 25 '18 at 21:32
AuroraAurora
1098
asked Nov 25 '18 at 21:32
AuroraAurora
1098
asked Nov 25 '18 at 21:32
AuroraAurora
1098
asked Nov 25 '18 at 21:32
AuroraAurora
1098
1098
3
No, that is pretty much the same thing, except your first example doesn't need the temp variable so looks cleaner, easier to read etc. If you are ever unsure about things like this, just put print statements in your code to see what's happening.
– SuperShoot
Nov 25 '18 at 21:34
2
It is only evaluated once
– juanpa.arrivillaga
Nov 25 '18 at 21:35
3
You could test this yourself by printing a message inhelper(), and seeing if that message gets printed once, or more than once.
– John Gordon
Nov 25 '18 at 21:37
Got it, thanks!
– Aurora
Nov 25 '18 at 21:42
Yeah, adding some so-simple-it’s-a-no-brainerprintstatements is all you need to go fromwonderingToknowing
– barny
Nov 25 '18 at 21:57
add a comment |
3
No, that is pretty much the same thing, except your first example doesn't need the temp variable so looks cleaner, easier to read etc. If you are ever unsure about things like this, just put print statements in your code to see what's happening.
– SuperShoot
Nov 25 '18 at 21:34
2
It is only evaluated once
– juanpa.arrivillaga
Nov 25 '18 at 21:35
3
You could test this yourself by printing a message inhelper(), and seeing if that message gets printed once, or more than once.
– John Gordon
Nov 25 '18 at 21:37
Got it, thanks!
– Aurora
Nov 25 '18 at 21:42
Yeah, adding some so-simple-it’s-a-no-brainerprintstatements is all you need to go fromwonderingToknowing
– barny
Nov 25 '18 at 21:57
3
3
No, that is pretty much the same thing, except your first example doesn't need the temp variable so looks cleaner, easier to read etc. If you are ever unsure about things like this, just put print statements in your code to see what's happening.
– SuperShoot
Nov 25 '18 at 21:34
No, that is pretty much the same thing, except your first example doesn't need the temp variable so looks cleaner, easier to read etc. If you are ever unsure about things like this, just put print statements in your code to see what's happening.
– SuperShoot
Nov 25 '18 at 21:34
2
2
It is only evaluated once
– juanpa.arrivillaga
Nov 25 '18 at 21:35
It is only evaluated once
– juanpa.arrivillaga
Nov 25 '18 at 21:35
3
3
You could test this yourself by printing a message in
helper(), and seeing if that message gets printed once, or more than once.– John Gordon
Nov 25 '18 at 21:37
You could test this yourself by printing a message in
helper(), and seeing if that message gets printed once, or more than once.– John Gordon
Nov 25 '18 at 21:37
Got it, thanks!
– Aurora
Nov 25 '18 at 21:42
Got it, thanks!
– Aurora
Nov 25 '18 at 21:42
Yeah, adding some so-simple-it’s-a-no-brainer
print statements is all you need to go from wondering To knowing– barny
Nov 25 '18 at 21:57
Yeah, adding some so-simple-it’s-a-no-brainer
print statements is all you need to go from wondering To knowing– barny
Nov 25 '18 at 21:57
add a comment |
1 Answer
1
active
oldest
votes
use the yield operation:
def helper():
for i in [1,2,3]:
yield i
for i in helper():
print(i)
in this case the helper() method would return the i value during each iteration to the calling for loop.
answered Nov 26 '18 at 6:27
Gautham MGautham M
234110
Cool, thanks so much for your answer.
– Aurora
Nov 27 '18 at 18:25
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
use the yield operation:
def helper():
for i in [1,2,3]:
yield i
for i in helper():
print(i)
in this case the helper() method would return the i value during each iteration to the calling for loop.
answered Nov 26 '18 at 6:27
Gautham MGautham M
234110
Cool, thanks so much for your answer.
– Aurora
Nov 27 '18 at 18:25
add a comment |
use the yield operation:
def helper():
for i in [1,2,3]:
yield i
for i in helper():
print(i)
in this case the helper() method would return the i value during each iteration to the calling for loop.
answered Nov 26 '18 at 6:27
Gautham MGautham M
234110
Cool, thanks so much for your answer.
– Aurora
Nov 27 '18 at 18:25
add a comment |
use the yield operation:
def helper():
for i in [1,2,3]:
yield i
for i in helper():
print(i)
in this case the helper() method would return the i value during each iteration to the calling for loop.
answered Nov 26 '18 at 6:27
Gautham MGautham M
234110
use the yield operation:
def helper():
for i in [1,2,3]:
yield i
for i in helper():
print(i)
in this case the helper() method would return the i value during each iteration to the calling for loop.
answered Nov 26 '18 at 6:27
Gautham MGautham M
234110
answered Nov 26 '18 at 6:27
Gautham MGautham M
234110
answered Nov 26 '18 at 6:27
Gautham MGautham M
234110
answered Nov 26 '18 at 6:27
Gautham MGautham M
234110
234110
Cool, thanks so much for your answer.
– Aurora
Nov 27 '18 at 18:25
add a comment |
Cool, thanks so much for your answer.
– Aurora
Nov 27 '18 at 18:25
Cool, thanks so much for your answer.
– Aurora
Nov 27 '18 at 18:25
Cool, thanks so much for your answer.
– Aurora
Nov 27 '18 at 18:25
add a comment |
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3
No, that is pretty much the same thing, except your first example doesn't need the temp variable so looks cleaner, easier to read etc. If you are ever unsure about things like this, just put print statements in your code to see what's happening.
– SuperShoot
Nov 25 '18 at 21:34
2
It is only evaluated once
– juanpa.arrivillaga
Nov 25 '18 at 21:35
3
You could test this yourself by printing a message in
helper(), and seeing if that message gets printed once, or more than once.– John Gordon
Nov 25 '18 at 21:37
Got it, thanks!
– Aurora
Nov 25 '18 at 21:42
Yeah, adding some so-simple-it’s-a-no-brainer
printstatements is all you need to go fromwonderingToknowing– barny
Nov 25 '18 at 21:57