for loop length of array python

stackoverflow.com › questions › 14532875 › creating-for-loop-until-list-length

In Python you can iterate over the list itself:

for item in my_list:
   #do something with item

or to use indices you can use xrange():

for i in xrange(1,len(my_list)):    #as indexes start at zero so you 
                                    #may have to use xrange(len(my_list))
    #do something here my_list[i]

There's another built-in function called enumerate(), which returns both item and index:

for index,item in enumerate(my_list):
    # do something here

examples:

In [117]: my_lis=list('foobar')

In [118]: my_lis
Out[118]: ['f', 'o', 'o', 'b', 'a', 'r']

In [119]: for item in my_lis:
    print item
   .....:     
f
o
o
b
a
r

In [120]: for i in xrange(len(my_lis)):
    print my_lis[i]
   .....:     
f
o
o
b
a
r

In [122]: for index,item in enumerate(my_lis):
    print index,'-->',item
   .....:     
0 --> f
1 --> o
2 --> o
3 --> b
4 --> a
5 --> r

Answer from Ashwini Chaudhary on Stack Overflow

Stack Overflow

stackoverflow.com › questions › 74750331 › iterating-through-a-for-loop-with-the-size-of-an-array

python - Iterating through a for loop with the size of an array - Stack Overflow

I want my program to be able to print out the sum of all numbers below n that are divisible by 3 and also 5. #!/bin/python3 import sys import math arr = [] arr3 = [] arr5 = [] tn = 1 sum1 = 0 sum...

python - How do I iterate through part of an array and why doesn't my loop work?

Python for loop and arrays

Python 'For' Loop Iterate Array

python loop array

How do I loop though the length of an array inside of another array in Python?

More results from stackoverflow.com

CodeGym

codegym.cc › java blog › learning python › length of an array in python

Length of an Array in Python

November 7, 2024 - Alternatively, you can write your own function using a for loop to count the elements manually. The simplest and most common method is, of course, using len(). It's efficient, readable, and works with different types of arrays.

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python - Creating for loop until list.length - Stack Overflow

I'm reading about for loops right now, and I am curious if it's possible to do a for loop in Python like in Java. Is it even possible to do something like for (int i = 1; i More on stackoverflow.com

stackoverflow.com

Loop over array elements without knowing length

Either your array is static or it's dynamic. If the array is static you know its length even if you don't explicity set it to a known length. You can do this int array[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; const int ARRAYLEN = (sizeof(array) / sizeof(array[0])); Use the ARRAYLEN value in your code. If the array is dynamic (malloc(), etc) you need to keep track of the array size, there's no other way. More on reddit.com

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September 6, 2024

Why iterate over an array using the index?

You do it if there is something in your loop that will use an index rather than the elements of the array. For instance, sometimes you want to sample something from another array that is not your loop array A cleaner way to do it is by using enumerate function for i, item in enumerate(array): The index gets assigned to i and whatever element of the array gets assigned to item. This may also be a bad habit from Matlab, people that come from Matlab are more used to looping over indexes. More on reddit.com

r/learnpython

April 22, 2023

What's the python version of (i=0;i<array.length;i++)? for x in list doesn't work as expected.

I think this is an XY problem. Explain exactly what you're trying to accomplish and why and how it's not working. for x in y: is the way it ought to be expressed in 99.9% of cases.

Top answer

1 of 4

In Python you can iterate over the list itself:

for item in my_list:
   #do something with item

or to use indices you can use xrange():

for i in xrange(1,len(my_list)):    #as indexes start at zero so you 
                                    #may have to use xrange(len(my_list))
    #do something here my_list[i]

There's another built-in function called enumerate(), which returns both item and index:

for index,item in enumerate(my_list):
    # do something here

examples:

In [117]: my_lis=list('foobar')

In [118]: my_lis
Out[118]: ['f', 'o', 'o', 'b', 'a', 'r']

In [119]: for item in my_lis:
    print item
   .....:     
f
o
o
b
a
r

In [120]: for i in xrange(len(my_lis)):
    print my_lis[i]
   .....:     
f
o
o
b
a
r

In [122]: for index,item in enumerate(my_lis):
    print index,'-->',item
   .....:     
0 --> f
1 --> o
2 --> o
3 --> b
4 --> a
5 --> r

2 of 4

Yes you can, with range ^[docs]:

for i in range(1, len(l)):
    # i is an integer, you can access the list element with l[i]

but if you are accessing the list elements anyway, it's more natural to iterate over them directly:

for element in l:
   # element refers to the element in the list, i.e. it is the same as l[i]

If you want to skip the the first element, you can slice the list ^[tutorial]:

for element in l[1:]:
    # ...

can you do another for loop inside this for loop

Sure you can.

iO Flood

ioflood.com › blog › get-length-of-array-in-python-guide-and-examples

Get Length of Array in Python: Guide and Examples

March 12, 2024 - As such, it’s generally recommended to use len() instead. An alternative method to calculate the length of an array involves using a for loop to iterate over the array and count the number of elements.

Naiveskill

naiveskill.com › home › determine python array length | complete tutorial with examples in 2023

Determine python array length | Complete tutorial with examples in 2023 - Naiveskill

January 4, 2023 - To find the length of an array in Python, you can use the len() function. The len() function in Python returns the length of an object, which is the number of elements present in an object. The syntax for the len() function in Python is as follows:

CodeRivers

coderivers.org › blog › length-of-an-array-python

Understanding the Length of an Array in Python - CodeRivers

February 22, 2026 - In Python, lists are a versatile data structure that can hold elements of different data types. The length of a list (array) refers to the number of elements it contains. This length is an important property as it helps in determining the size of the data collection and is crucial for operations that need to access or manipulate all the elements.

Thinkincode

thinkincode.net › python › length-of-array-python

Calculating Array Length in Python | ThinkInCode

# Example my_array = [1, 2, 3, 4, 5] length = 0 for element in my_array: length += 1 print("Length of the array:", length) NumPy is a popular numerical computing library in Python. It provides a numpy array that is more efficient for numerical operations than a regular Python list.

CodeRivers

coderivers.org › blog › python-length-of-an-array

Python Length of an Array: A Comprehensive Guide — CodeRivers

In this case, the size attribute returns the total number of elements in the NumPy array. For a 2D array, it gives the product of the number of rows and columns. Here, the array has 2 rows and 3 columns, so the size is 6. One common practice is to use the length of an array to loop through its elements.

reddit.com › r/arduino › loop over array elements without knowing length

r/arduino on Reddit: Loop over array elements without knowing length

September 6, 2024 -

How do I write a for loop that goes through all the elements of an array in a way that ensures that the length is respected?

If I already know what the length is, I can do something like:

int array[5] {1, 2, 3, 4, 5}
for (int i = 0; i < 5; i++){
  println(array[i]);
}

But what if I don't know the length, or don't want to manually keep track? Can I do something like the python

for element in array:
  print(element)

for i in range(len(array)):
  print (array(i))

It looks like Arduino has the sizeof() command, but that seems to be getting a size in bytes, rather than a "number of elements", which isn't useful for this purpose if you're reading off a bunch of long floats.