====== Python code snippets ======

===== FOR loop =====

Looping through all the items in a dictionary.

==== Print all the keys ====

<code python>
exampledict =	{
  "class": "Modified Hall",
  "engine": "Witherslack Hall",
  "built": "1948"
}
for x in thisdict:
  print(x)
</code>
<code>
class
engine
built
</code>


==== Print all the values - version 1 ====

<code python>
exampledict =	{
  "class": "Modified Hall",
  "engine": "Witherslack Hall",
  "built": "1948"
}
for x in exampledict:
  print(exampledict[x])
</code>

<code>
Modified Hall
Witherslack Hall
1948
</code>


==== Print all the values - version 2 ====

This uses the Python ".values()" function to get the values of each dictionary item.
<code python>
exampledict =	{
  "class": "Modified Hall",
  "engine": "Witherslack Hall",
  "built": "1948"
}
for x in exampledict.values():
  print(x)
</code>

<code>
Modified Hall
Witherslack Hall
1948
</code>


==== Print both keys and values ====

Using the "items()" function to return both the value and the key for wach item.

<code python>
exampledict =	{
  "class": "Modified Hall",
  "engine": "Witherslack Hall",
  "built": "1948"
}
for x,y in exampledict.items():
  print(x, y)
</code>

<code>
class Modified Hall
engine Witherslack Hall
built 1948
</code>





===== CLI input selection for an option =====

<code python>
# select option in cli
print("1 - pass")
print("2 - fail")
print("3 - converted")

selection = input("Please select an option:- ")
print(selection)
</code>

===== Case statement =====

<code python>
# path = 'pass'
path = 'fail'

match path:
    case 'pass':
        route = 'pass'
    case 'fail':
        route = 'fail'
    case _:
        route = 'not defined'

print(route)
</code>


===== Dictionary.get method =====

<code python>
table_name = {'Parameter': {'Name': 'DynamoTableName', 'Type': 'String', 'Value': 'DB-development', 'ARN': 'arn:aws:ssm:eu-west-2:123456789:DynamoTableName', 'DataType': 'text'}}

# Just reference the Dictionary Value
value = table_name['Parameter']['Value']
print("Value is:- ", value)


# Use two .get methods to dig into nested dictionary
testval = table_name.get('Parameter').get('Value')
print("Test Val:-", testval)

</code>

Gives:-

<code>
Value is:- DB-development
Test Val:- DB-development
</code>





===== Read in file, line by line =====

Read in the first line to set line to a true value, then iterate until line is false:-


<code>
with open('mytext.txt') as file:
    line = file.readline()
    while line:
        print(line, end='')
        line = file.readline()
        
</code>











===== Copy Binary file =====

Text mode (t) is the default, use ''b'' to do a binary (bytes) copy:-

<code python>
with open('logo.jpg', 'rb') as readf:
    with open('logo_new.jpg', 'wb') as writef:
        for b in readf:
            writef.write(b)
</code>


===== Working with Datetime =====

Rounding to seconds by replacing microseconds and adding integer to datetime with ''timedelta'':-

<code python>
app.config['SESSION_COOKIE_LIFETIME'] = 120

cookie_expiry = datetime.now().replace(microsecond=0) + timedelta(seconds=app.config['SESSION_COOKIE_LIFETIME'])
</code>

===== SQL for datetime related stuff =====

<code sql>
> describe user_model;
+------------------+--------------+------+-----+---------------------+----------------+
| Field            | Type         | Null | Key | Default             | Extra          |
+------------------+--------------+------+-----+---------------------+----------------+
| id               | int(11)      | NO   | PRI | NULL                | auto_increment |
| user_id          | varchar(255) | NO   | UNI | NULL                |                |
| date_last_update | timestamp    | YES  |     | current_timestamp() |                |
| login_status     | tinyint(1)   | NO   |     | NULL                |                |
| cookie_expiry    | timestamp    | NO   |     | 0000-00-00 00:00:00 |                |
+------------------+--------------+------+-----+---------------------+----------------+
5 rows in set (0.001 sec)

</code>

Select rows where timestamp is in the past:-

> SELECT * FROM `user_model` WHERE `cookie_expiry` < NOW();