Finding Index for 0Hz on RF Spectrum

[Erenjaeger]

Homework Statement

Find the index corresponding to 0Hz on my RF spectrum vs frequency garph

Homework Equations

using np.argmax or np.argmin [/B]

The Attempt at a Solution

np.argmin just gives the proof that the lowest value in frequency array plotted on x-axis is 0, but now i need to find the index in the array where this happens so i can set the RF spectrum to 0 at that value in order to determine frep or a laser. [/B]

 

[Erenjaeger]

Homework Statement

Find the index corresponding to 0Hz on my RF spectrum vs frequency garph

Homework Equations

using np.argmax or np.argmin [/B]

The Attempt at a Solution

np.argmin just gives the proof that the lowest value in frequency array plotted on x-axis is 0, but now i need to find the index in the array where this happens so i can set the RF spectrum to 0 at that value in order to determine frep or a laser. [/B]

in python 3 btw

 

[Mark44]

Homework Statement

Find the index corresponding to 0Hz on my RF spectrum vs frequency garph

Homework Equations

using np.argmax or np.argmin [/B]

The Attempt at a Solution

np.argmin just gives the proof that the lowest value in frequency array plotted on x-axis is 0, but now i need to find the index in the array where this happens so i can set the RF spectrum to 0 at that value in order to determine frep or a laser. [/B]

Can't you just iterate through the array, keeping track of what index you're on, and see when the array value is 0?

 

[Erenjaeger]

Can't you just iterate through the array, keeping track of what index you're on, and see when the array value is 0?

Not sure how you would code that though I have to write a piece of code that does it, seems simple but I can't find any information on how to find the index where frequency is 0

 

[Mark44]

Here's an example of what I'm talking about:

import array

arr0 = array.array('i', [3, 17, -1, 0, 5, 23, 18])
found = False

for i in range(len(arr0)):
   if arr0[i] == 0:
      found = True
      print("Found 0 at index ", i)
if found == False:
   print("Could not find 0")

If one of the values in the array happens to be zero, this code prints the corresponding index where it was found. If the array doesn't contain 0, the code displays a message that zero couldn't be found.

 

[Erenjaeger]

Here's an example of what I'm talking about:

import array

arr0 = array.array('i', [3, 17, -1, 0, 5, 23, 18])
found = False

for i in range(len(arr0)):
   if arr0[i] == 0:
      found = True
      print("Found 0 at index ", i)
if found == False:
   print("Could not find 0")

If one of the values in the array happens to be zero, this code prints the corresponding index where it was found. If the array doesn't contain 0, the code displays a message that zero couldn't be found.

The array is stored under a variable "f2" which is the x-axis and then "RF signal" which is the y axis, I tried running your code with f2 as the array but it didn't run. any idea why that might have been?

 

[mfb]

Can you show the code and the error message (or whatever was the result of running the code)?

 

[Erenjaeger]

Can you show the code and the error message (or whatever was the result of running the code)?

Yep! attached is the screen shot and also I printed the array "f2" so you could get an idea of what it consists of.

 

[Erenjaeger]

Yep! attached is the screen shot and also I printed the array "f2" so you could get an idea of what it consists of.
View attachment 213956

I thought it might be taking f2 as a single element of the array rather than an array itself because that error message about length-1 arrays?

 

[mfb]

What exactly do you expect "arr0=array.array('i',[f2])" to do? Why don't you iterate over f2 and get rid of arr0?

 

[Mark44]

In my example, I created the array named arr0. This array contains integers, which is the reason for 'i' in the statement arr0 = array.array('i', ...). Since you already have an array, f2, you don't need to create one. As @mfb suggests, just iterate over the array you have.