user1075: Using the blockfrost API I quired the transaction history of a NFT using the following script:

from blockfrost import BlockFrostApi, ApiError, ApiUrls


api = BlockFrostApi(
    project_id='my_secret_key',  
    base_url=ApiUrls.mainnet.value,
)

try:
    health = api.health()
    print(health) 

    assets = api.assets_policy(my_policy_id)
    asset_history = api.asset_transactions(assets[13].asset, return_type='pandas')
    print(asset_history)

except ApiError as e:
    print(e)

Getting this response:
                                              tx_hash  tx_index  block_height  block_time
0   38ad1c10fce2ff3cc19a47002ea3f0e42257a56d051dc3...         2       6436806  1635591940
1   c379a46550f041e3dd25d534034beb71b04f15ce3f65b1...         7       6439385  1635644577
2   d92447f19d78cae77b57d727ee459e2665839990418233...        37       6439387  1635644654
3   1c6e774d35c6196d6236f0465ca162a5b873a846b2a5eb...        13       6439391  1635644697
4   5c1048c319fcfca8ba8f6992ae894be73c9244d78d9947...        18       6439398  1635644851
5   f71f698da38403c475565c109a143bda06fb87f718ec08...        34       6439401  1635644928
6   e15fb6c7fdc5ccc6ccef234f0645b510f150bf7b2e74b4...        18       6439533  1635647419
7   479995eea8a566384eec7b8933c55ef83db42b08779538...         2       6440258  1635663466
8   0548dab5b72458d0ea31b0e99f13c671d4634d27657e03...         0       6440355  1635665472
9   94141bcb58cdb5822b9fea7eab9b8868845d523f9f190d...         8       6441301  1635685169
10  738bed4f7bccfa426a403e35845bee96c0d3f41e83ea5e...        13       6441422  1635687392
11  4afb4df1d193ceb3bfe24d9de934252a176120888e0a96...         0       6442330  1635706804
12  4e847c23f326821b3565472045e36ea774f496df2f09a5...        70       6442428  1635708878
13  cb19e1da6665375c1b6b3ac1e0e31bb238b1f1c90000f3...         6       6444826  1635758501
14  6ec8b61254f82120c6120a24d41e50977abf613f5c66b7...        23       6445035  1635762659
15  5e644b9c77d6c565c925d15cfecfffd7a279eb9a2c713e...        31       6447594  1635814038
16  8db58815ee4ad5f37aaaddbd7d1ef8719477a87d24452d...         4       6447605  1635814237
17  11fd5b552be255831d82fdc513fff41c4809cf33e7c6b2...        12       6447776  1635818167
18  b05dd10d64764ae7b9aab93c3b1e7ddaa2a6c9c0680461...        26       6462608  1636121671
19  22a8c33a6fe35fd82cfd00544bda4345ea65318188a927...        25       6462612  1636121753
20  f9882f6aea766d9f5a3b503f168c84b635e9be0a349acd...         7       6462673  1636122903
21  0a6fa23b9081d938e986734071ab66c7032f6c50954428...        22       6462904  1636128077
22  8450c04442ba42432edc4d7d1c703e084e28e6ab3e9f8d...         4       6463391  1636138353
23  ade1f612f6d7adcb54c3a804cdb230f343b486f425f32c...         0       6468943  1636250015
24  13fb4e318ba12558819ede20ed37dc2bef7b9dae7cff61...        26       6469165  1636254523
25  3153d200935012eb695ffafd13ffe68c04c4f2fc179c9a...         4       6469171  1636254605
26  fb5e69b4ddb00f23cbe879c2087fe315178ac73fa07c56...        22       6469172  1636254670
27  9555c42315f15a88b29535ebffc05369ccc9b2fc092db8...         4       6482371  1636529118
28  09e430ad3ffde4f1e21fe33564f29a0fbb699213df67f8...         9       6483131  1636544549
29  8949eed31b7cede95c294f0bdec3d6b26ded6b14a18adb...        35       6485203  1636585696
30  50a06e0f0cc53e666d474798f5bc05bffcc1812fd23524...        31       6485216  1636585952
31  e0401628a403a699d91610439606f406d82c9fa4cf655f...        28       6485336  1636588252
32  89a311b10d004da25b3027d4795fc2e245a59a6be30c5e...        54       6485341  1636588391
33  e7b5c1b24ae39bf0f10000237bee03254ea0ac67399002...        16       6485394  1636589435
34  3a319385fe7a8373e3c0ac864727147ccb3edb409abac8...         8       6485404  1636589609
35  7f4a9bd753caae61e6e7e7147269ab6500832aab8d786c...         8       6485406  1636589642
36  1b0965031f3e137f9d787941230894ccf91d89d0beb6b9...        20       6485430  1636590112
37  f526d275da39c46783983aa326da5fe13379270ab12b01...        13       6485447  1636590324
38  cbe3b65fd19364fab8e69062d9075dfa9f6ff90e25f02b...        26       6488527  1636651538

My questions:

Does each line represent a transaction where the NFT was transferred from one address to another address? If not, why are there so many transactions?

What is the tx_index?

Is the block height simply the size of the new block added to the
ledger? (in bytes?)

Where can I find a reference so that I can easily answer these
questions myself and not have to create a StackOverflow post each
time?



user28: 
Correct, that is the history of transaction of that specific asset
That is the index of the transaction within a block
block_height is the height of the block, in other words, it is the number of the block in the blockchain
Directly on docs.blockfrost.io, go to the specific endpoint and click on the 200 response to roll down the descriptions of each fields:



1075: <p>Using the blockfrost API I quired the transaction history of a NFT using the following script:</p>
<pre><code>
from blockfrost import BlockFrostApi, ApiError, ApiUrls


api = BlockFrostApi(
    project_id='my_secret_key',  
    base_url=ApiUrls.mainnet.value,
)

try:
    health = api.health()
    print(health) 

    assets = api.assets_policy(my_policy_id)
    asset_history = api.asset_transactions(assets[13].asset, return_type='pandas')
    print(asset_history)

except ApiError as e:
    print(e)
</code></pre>
<p>Getting this response:</p>
<pre><code>                                              tx_hash  tx_index  block_height  block_time
0   38ad1c10fce2ff3cc19a47002ea3f0e42257a56d051dc3...         2       6436806  1635591940
1   c379a46550f041e3dd25d534034beb71b04f15ce3f65b1...         7       6439385  1635644577
2   d92447f19d78cae77b57d727ee459e2665839990418233...        37       6439387  1635644654
3   1c6e774d35c6196d6236f0465ca162a5b873a846b2a5eb...        13       6439391  1635644697
4   5c1048c319fcfca8ba8f6992ae894be73c9244d78d9947...        18       6439398  1635644851
5   f71f698da38403c475565c109a143bda06fb87f718ec08...        34       6439401  1635644928
6   e15fb6c7fdc5ccc6ccef234f0645b510f150bf7b2e74b4...        18       6439533  1635647419
7   479995eea8a566384eec7b8933c55ef83db42b08779538...         2       6440258  1635663466
8   0548dab5b72458d0ea31b0e99f13c671d4634d27657e03...         0       6440355  1635665472
9   94141bcb58cdb5822b9fea7eab9b8868845d523f9f190d...         8       6441301  1635685169
10  738bed4f7bccfa426a403e35845bee96c0d3f41e83ea5e...        13       6441422  1635687392
11  4afb4df1d193ceb3bfe24d9de934252a176120888e0a96...         0       6442330  1635706804
12  4e847c23f326821b3565472045e36ea774f496df2f09a5...        70       6442428  1635708878
13  cb19e1da6665375c1b6b3ac1e0e31bb238b1f1c90000f3...         6       6444826  1635758501
14  6ec8b61254f82120c6120a24d41e50977abf613f5c66b7...        23       6445035  1635762659
15  5e644b9c77d6c565c925d15cfecfffd7a279eb9a2c713e...        31       6447594  1635814038
16  8db58815ee4ad5f37aaaddbd7d1ef8719477a87d24452d...         4       6447605  1635814237
17  11fd5b552be255831d82fdc513fff41c4809cf33e7c6b2...        12       6447776  1635818167
18  b05dd10d64764ae7b9aab93c3b1e7ddaa2a6c9c0680461...        26       6462608  1636121671
19  22a8c33a6fe35fd82cfd00544bda4345ea65318188a927...        25       6462612  1636121753
20  f9882f6aea766d9f5a3b503f168c84b635e9be0a349acd...         7       6462673  1636122903
21  0a6fa23b9081d938e986734071ab66c7032f6c50954428...        22       6462904  1636128077
22  8450c04442ba42432edc4d7d1c703e084e28e6ab3e9f8d...         4       6463391  1636138353
23  ade1f612f6d7adcb54c3a804cdb230f343b486f425f32c...         0       6468943  1636250015
24  13fb4e318ba12558819ede20ed37dc2bef7b9dae7cff61...        26       6469165  1636254523
25  3153d200935012eb695ffafd13ffe68c04c4f2fc179c9a...         4       6469171  1636254605
26  fb5e69b4ddb00f23cbe879c2087fe315178ac73fa07c56...        22       6469172  1636254670
27  9555c42315f15a88b29535ebffc05369ccc9b2fc092db8...         4       6482371  1636529118
28  09e430ad3ffde4f1e21fe33564f29a0fbb699213df67f8...         9       6483131  1636544549
29  8949eed31b7cede95c294f0bdec3d6b26ded6b14a18adb...        35       6485203  1636585696
30  50a06e0f0cc53e666d474798f5bc05bffcc1812fd23524...        31       6485216  1636585952
31  e0401628a403a699d91610439606f406d82c9fa4cf655f...        28       6485336  1636588252
32  89a311b10d004da25b3027d4795fc2e245a59a6be30c5e...        54       6485341  1636588391
33  e7b5c1b24ae39bf0f10000237bee03254ea0ac67399002...        16       6485394  1636589435
34  3a319385fe7a8373e3c0ac864727147ccb3edb409abac8...         8       6485404  1636589609
35  7f4a9bd753caae61e6e7e7147269ab6500832aab8d786c...         8       6485406  1636589642
36  1b0965031f3e137f9d787941230894ccf91d89d0beb6b9...        20       6485430  1636590112
37  f526d275da39c46783983aa326da5fe13379270ab12b01...        13       6485447  1636590324
38  cbe3b65fd19364fab8e69062d9075dfa9f6ff90e25f02b...        26       6488527  1636651538
</code></pre>
<p>My questions:</p>
<ul>
<li><p>Does each line represent a transaction where the NFT was transferred from one address to another address? If not, why are there so many transactions?</p>
</li>
<li><p>What is the tx_index?</p>
</li>
<li><p>Is the block height simply the size of the new block added to the
ledger? (in bytes?)</p>
</li>
<li><p>Where can I find a reference so that I can easily answer these
questions myself and not have to create a StackOverflow post each
time?</p>
</li>
</ul>
 28: <ul>
<li>Correct, that is the history of transaction of that specific asset</li>
<li>That is the index of the transaction within a block</li>
<li><code>block_height</code> is the height of the block, in other words, it is the number of the block in the blockchain</li>
<li>Directly on <a href="https://docs.blockfrost.io/" rel="nofollow noreferrer">docs.blockfrost.io</a>, go to the specific endpoint and click on the <code>200</code> response to roll down the descriptions of each fields:</li>
</ul>
<p><a href="https://i.stack.imgur.com/G3wnd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/G3wnd.png" alt="enter image description here" /></a></p>
