To find Oplog size using python - python

How to find oplog size in mongodb using python?
For example :
replGetSetStatus is equivalent to rs.status()
Is there any similar command to find rs.printReplicationInfo()
uri = "mongodb://usernamen:password#host:port/admin"
conn = pymongo.MongoClient(uri)
db = conn['admin']
db_stats = db.command({'replSetGetStatus' :1})
primary_optime = 0
secondary_optime = 0
for key in db_stats['members'] :
if key['stateStr'] == 'SECONDARY' :
secondary_optime = key['optimeDate']
if key['stateStr'] == 'PRIMARY' :
primary_optime =key['optimeDate']
print 'primary_optime : ' + str(primary_optime)
print 'secondary_optime : ' + str(secondary_optime)
seconds_lag = (primary_optime - secondary_optime ).total_seconds()
#total_seconds() userd to get the lag in seconds rather than datetime object
print 'secondary_lag : ' + str(seconds_lag)
This is my code. The db.command({'replSetGetStatus' :1}) is working.
Similarly I need for the oplog size.

The following commands executed from any replicaSet member will give you the size of oplog:
Uncompressed size in MB:
db.getReplicationInfo().logSizeMB
Uncompressed current size in Bytes:
db.getSiblingDB('local').oplog.rs.stats().size
Compressed current size in Bytes:
db.getSiblingDB('local').oplog.rs.stats().storageSize
Max configured size:
db.getSiblingDB('local').oplog.rs.stats().maxSize

Related

PySerial returning incorrect data from Nova PM SDS011 with raspi3

Here in California, I have purchased some Nova SDS011 PM sensors. When attempting to read from these sensors using Ivan Kalchev's git repo, I get mixed results. I can send commands to the sensor. e.g. sensor.sleep(sleep=<True/False>) will turn the fan on and off. However attempting to query the sensor to return PM2.5 and PM10 data returns a byte string that does not match the check sum. A couple examples are in the code snip-it below. As you can see, bytes 2 and 6 appear to be corrupt, and furthermore, the response is two bytes shorter than what is expected from the documentation.
Any Idea whats going on here? Im hoping this is simply a problem with pyserial. I have produced the same results with two sensors.
>>> sensor.sleep(sleep=False)
>>> cmd
'\xaa\xb4\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff\x02\xab'
>>> sensor.ser.write(cmd)
19
>>> sensor.ser.readline()
'\xaa\xc0]\x01\xba\x01\xc2*\x05\xab'
>>> sensor.ser.write(cmd)
19
>>> sensor.ser.readline()
'\xaa\xc0c\x01\xbc\x01\xc2*\r\xab'
>>> sensor.ser.write(cmd)
19
>>> sensor.ser.readline()
'\xaa\xc0d\x01\xbf\x01\xc2*\x11\xab'
So this occurred because the python was written for python 3, and my raspberry pi had 2.7. below is the code for 2.7. Thanks to Ivan for putting the original together.
"""This module provides an abstraction for the SDS011 air partuclate densiry sensor.
"""
import struct
import serial
#TODO: Commands against the sensor should read the reply and return success status.
class SDS011(object):
"""Provides method to read from a SDS011 air particlate density sensor
using UART.
"""
HEAD = b'\xaa'
TAIL = b'\xab'
CMD_ID = b'\xb4'
# The sent command is a read or a write
READ = b"\x00"
WRITE = b"\x01"
REPORT_MODE_CMD = b"\x02"
ACTIVE = b"\x00"
PASSIVE = b"\x01"
QUERY_CMD = b"\x04"
# The sleep command ID
SLEEP_CMD = b"\x06"
# Sleep and work byte
SLEEP = b"\x00"
WORK = b"\x01"
# The work period command ID
WORK_PERIOD_CMD = b'\x08'
def __init__(self, serial_port, baudrate=9600, timeout=2,
use_query_mode=True):
"""Initialise and open serial port.
"""
self.ser = serial.Serial(port=serial_port,
baudrate=baudrate,
timeout=timeout)
self.ser.flush()
self.set_report_mode(active=not use_query_mode)
def _execute(self, cmd_bytes):
"""Writes a byte sequence to the serial.
"""
self.ser.write(cmd_bytes)
def _get_reply(self):
"""Read reply from device."""
raw = self.ser.read(size=10)
data = raw[2:8]
if len(data) == 0:
return None
if (sum(ord(d) for d in data) & 255) != ord(raw[8]):
return None #TODO: also check cmd id
return raw
def cmd_begin(self):
"""Get command header and command ID bytes.
#rtype: list
"""
return self.HEAD + self.CMD_ID
def set_report_mode(self, read=False, active=False):
"""Get sleep command. Does not contain checksum and tail.
#rtype: list
"""
cmd = self.cmd_begin()
cmd += (self.REPORT_MODE_CMD
+ (self.READ if read else self.WRITE)
+ (self.ACTIVE if active else self.PASSIVE)
+ b"\x00" * 10)
cmd = self._finish_cmd(cmd)
self._execute(cmd)
self._get_reply()
def query(self):
"""Query the device and read the data.
#return: Air particulate density in micrograms per cubic meter.
#rtype: tuple(float, float) -> (PM2.5, PM10)
"""
cmd = self.cmd_begin()
cmd += (self.QUERY_CMD
+ b"\x00" * 12)
cmd = self._finish_cmd(cmd)
self._execute(cmd)
raw = self._get_reply()
if raw is None:
return None #TODO:
data = struct.unpack('<HH', raw[2:6])
pm25 = data[0] / 10.0
pm10 = data[1] / 10.0
return (pm25, pm10)
def sleep(self, read=False, sleep=True):
"""Sleep/Wake up the sensor.
#param sleep: Whether the device should sleep or work.
#type sleep: bool
"""
cmd = self.cmd_begin()
cmd += (self.SLEEP_CMD
+ (self.READ if read else self.WRITE)
+ (self.SLEEP if sleep else self.WORK)
+ b"\x00" * 10)
cmd = self._finish_cmd(cmd)
self._execute(cmd)
self._get_reply()
def set_work_period(self, read=False, work_time=0):
"""Get work period command. Does not contain checksum and tail.
#rtype: list
"""
assert work_time >= 0 and work_time <= 30
cmd = self.cmd_begin()
cmd += (self.WORK_PERIOD_CMD
+ (self.READ if read else self.WRITE)
+ bytes([work_time])
+ b"\x00" * 10)
cmd = self._finish_cmd(cmd)
self._execute(cmd)
self._get_reply()
def _finish_cmd(self, cmd, id1=b"\xff", id2=b"\xff"):
"""Add device ID, checksum and tail bytes.
#rtype: list
"""
cmd += id1 + id2
checksum = sum(d for d in bytearray(cmd[2:])) % 256
cmd += chr(checksum) + self.TAIL
return cmd
def _process_frame(self, data):
"""Process a SDS011 data frame.
Byte positions:
0 - Header
1 - Command No.
2,3 - PM2.5 low/high byte
4,5 - PM10 low/high
6,7 - ID bytes
8 - Checksum - sum of bytes 2-7
9 - Tail
"""
raw = struct.unpack('<HHxxBBB', data[2:])
checksum = sum(v for v in bytearray(data[2:8])) % 256
if checksum != data[8]:
return None
pm25 = raw[0] / 10.0
pm10 = raw[1] / 10.0
return (pm25, pm10)
def read(self):
"""Read sensor data.
#return: PM2.5 and PM10 concetration in micrograms per cude meter.
#rtype: tuple(float, float) - first is PM2.5.
"""
byte = 0
while byte != self.HEAD:
byte = self.ser.read(size=1)
d = self.ser.read(size=10)
if d[0:1] == b"\xc0":
data = self._process_frame(byte + d)
return data

How to parse Log file to object list

I'm working with data tipe Log (ROS).
Multiple objects are saved in Log file like this:
header:
seq: 2
stamp:
secs: 1596526199
nsecs: 140017032
frame_id: ''
level: 2
name: "/replicator_node"
msg: "Replicator node dumping to /tmp/replicator_dumps"
file: "replicator_node.py"
function: "__init__"
line: 218
topics: [/move_mongodb_entries/status, /move_mongodb_entries/goal, /move_mongodb_entries/result,
/move_mongodb_entries/cancel, /rosout, /move_mongodb_entries/feedback]
header:
seq: 2
stamp:
secs: 1596526198
nsecs: 848793029
frame_id: ''
level: 2
name: "/mongo_server"
msg: "2020-08-04T09:29:58.848+0200 [initandlisten] connection accepted from 127.0.0.1:58672\
\ #1 (1 connection now open)"
file: "mongodb_server.py"
function: "_mongo_loop"
line: 139
topics: [/rosout]
As you can see not everything is in same line as it's name.
I want to pars it to have object list - so I could access it like that:
object[1].msg would give me:
"2020-08-04T09:29:58.848+0200 [initandlisten] connection accepted from 127.0.0.1:58672 #1 (1 connection now open)"
Also, sometimes file name is something like: \home\nfoo\foo.py which results in log file as:
file: "\home
foo\foo.py"
It's an interesting exercise... Assuming that the structure is really consistent for all log entries, you can try something like this - pretty convoluted, but it works for the example in the question:
ros = """[your log above]"""
def manage_lists_2(log_ind, list_1, list_2, mystr):
if log_ind == 0:
list_1.append(mystr.split(':')[0].strip())
list_2[-log_ind].append(mystr.split(':')[1].strip())
m_keys2 = []
m_key_vals2 = [[],[]]
header_keys2 = []
header_key_vals2 = [[],[]]
stamp_keys2 = []
stamp_key_vals2 = [[],[]]
for log in logs:
for l in log.splitlines():
if l[0]!=" ":
items = [m_keys2, m_key_vals2]
elif l[0:3] != " ":
items = [header_keys2, header_key_vals2]
else:
items = [stamp_keys2, stamp_key_vals2]
manage_lists_2(logs.index(log), items[0], items[1], l)
for val in m_key_vals2:
for a, b, in zip(m_keys2,val):
print(a, ": ",b)
if a == "header":
for header_key in header_keys2:
print('\t',header_key,':',header_key_vals2[m_keys2.index(a)][header_keys2.index(header_key)])
if header_key == "stamp":
for stamp_key in stamp_keys2:
print('\t\t',stamp_key,':',stamp_key_vals2[m_keys2.index(a)][stamp_keys2.index(stamp_key)])
print('---')
Output:
header :
seq : 2
stamp :
secs : 1596526199
nsecs : 140017032
frame_id : 'one id'
level : 2
name : "/replicator_node"
msg : "Replicator node dumping to /tmp/replicator_dumps"
file : "replicator_node.py"
function : "__init__"
line : 218
topics : [/move_mongodb_entries/status, /move_mongodb_entries/goal, /move_mongodb_entries/result, /move_mongodb_entries/cancel, /rosout, /move_mongodb_entries/feedback]
---
header :
seq : 2
stamp :
secs : 1596526199
nsecs : 140017032
frame_id : 'one id'
level : 3
name : "/mongo_server"
msg : "2020-08-04T09
file : "mongodb_server.py"
function : "_mongo_loop"
line : 139
topics : [/rosout]
Having gone through that, I would recommend that - if you are going to do this on a regular basis - you find a way to store the data in xml format; it's a natural fit for it.

How to dynamically print list in Python

We're working on a Python project, where we are retrieving data from our MySQL database, and we're then sending it back to a new table on our database. We have initialized a list,
list_lpn_temp = []
The problem is that the range of this list varies, and therefore we don't always know how many datapoints we will have in our list. We have this code, and this is where the error occurs:
df2 = pd.DataFrame(columns=['first_temp_lpn', 'first_temp_lpn_validated', 'second_temp_lpn', 'second_temp_lpn_validated', 'third_temp_lpn', 'third_temp_lpn_validated'])
df2 = df2.append({'first_temp_lpn' : list_lpn_temp[0][0], 'first_temp_lpn_validated' : list_validated[0], 'second_temp_lpn' : list_lpn_temp[1][0], 'second_temp_lpn_validated' : list_validated[1], 'third_temp_lpn' : list_lpn_temp[2][0], 'third_temp_lpn_validated' : list_validated[2]}, ignore_index=True).round(2)
with engine.connect() as conn, conn.begin():
df2.to_sql('Raw_Validated', conn, if_exists='append', index=False)
Sometimes it gives us an error saying index out of range, as we sometimes only have 2 values in the list, and therefore list_lpn_temp[3][0] will give us the error. Dream scenario would be, if we could somehow send a null or maybe some text saying that we dont have any value to our database.
Therefore we need 2 things:
Send data, but where it depends on the size of our list, and is not just set static. For example like this (We need something better than this):
'first_temp_lpn' : list_lpn_temp[0][0]
If we are receiving index out of range, then we still need to send something to the database, as it expects 3x columns of temperature. But as there are no values, we could send a null, and therefore this could be nice to implement. Otherwise we will just get another big issue.
BIGGER PART OF THE CODE
engine = create_engine("mysql://xxx:xxx#localhost/xxx")
conn = engine.connect()
list_lpn_temp = []
index = pd.date_range(start=start_range.min(), end=end_range.max(), freq='20T')
for x in index:
a_temp = pd.read_sql('SELECT temperature FROM Raw_Data', conn).astype(float).values
list_lpn_temp.extend(a_temp)
if len(list_lpn_temp) > max_samples:
list_lpn_temp.pop(0)
for i in range (len(list_lpn_temp)):
if -1.5 < 25-list_lpn_temp[i] < 1.5:
validated_lpn = 1
list_validated.append(validated_lpn)
new_list_lpn_temp.extend(list_lpn_temp[i])
else:
validated_lpn = 0
list_validated.append(validated_lpn)
df2 = pd.DataFrame(columns=['first_temp_lpn', 'first_temp_lpn_validated', 'second_temp_lpn', 'second_temp_lpn_validated', 'third_temp_lpn', 'third_temp_lpn_validated'])
df2 = df2.append({'first_temp_lpn' : list_lpn_temp[0][0], 'first_temp_lpn_validated' : list_validated[0], 'second_temp_lpn' : list_lpn_temp[1][0], 'second_temp_lpn_validated' : list_validated[1], 'third_temp_lpn' : list_lpn_temp[2][0], 'third_temp_lpn_validated' : list_validated[2]}, ignore_index=True).round(2)
with engine.connect() as conn, conn.begin():
df2.to_sql('Raw_Validated', conn, if_exists='append', index=False)
NEW (KP)
We have a time_start and time_end value, which is formatted to datetime. We want to send it with the temp, so we have tried to modify the df2.append.
lastTime = pd.read_sql('SELECT MAX(timestamp) FROM Raw_Data', conn).astype(str).values.tolist()
firstTime = pd.read_sql('SELECT MIN(timestamp) FROM Raw_Data', conn).astype(str).values.tolist()
firstTime = (pd.to_datetime(firstTime[0])-datetime.timedelta(minutes=10)).round('20T')
lastTime = (pd.to_datetime(lastTime[0])-datetime.timedelta(minutes=10)).round('20T')
test = lastTime - datetime.timedelta(minutes=40)
time_start = test.astype(str).values[0]
lastTime = lastTime + datetime.timedelta(minutes=20)
time_end = lastTime.astype(str).values[0]
for name, value, valid in zip(['first', 'second', 'third'], list_lpn_temp, list_validated):
temp[name+'_temp_lpn'] = value[0]
temp[name+'_temp_lpn_validated'] = valid
df2 = df2.append({'time_start' : time_start, 'time_end' : time_end}, temp)
print (df2)
But then only datetime is being sent (time_start and time_end)
you can loop over the elements in the list.
Something like
temp = {}
for name, value in zip(['first', 'second', 'third'], list_lpn_temp):
temp[name+'_temp_lpn'] = value[0]
temp[name+'_temp_lpn_validated'] = value[1]
df2 = df2.append(temp)

Error using GetExtendedTcpTable in python

I've got some troubles with using "GetExtendedTcpTable". When I tried to run my script, i've got message like this:
AssertionError: [Error 0] The operation completed successfully
Rarely script working normally, I dont understand this message, Operation completed, what`s wrong?
This is code, i tried to execute:
from ctypes import *
from ctypes.wintypes import *
from socket import inet_aton, inet_ntoa, htons
AF_INET = 2
TCP_TABLE_BASIC_LISTENER = 0
TCP_TABLE_BASIC_CONNECTIONS = 1
TCP_TABLE_BASIC_ALL = 2
TCP_TABLE_OWNER_PID_LISTENER = 3
TCP_TABLE_OWNER_PID_CONNECTIONS = 4
TCP_TABLE_OWNER_PID_ALL = 5
TCP_TABLE_OWNER_MODULE_LISTENER = 6
TCP_TABLE_OWNER_MODULE_CONNECTIONS = 7
TCP_TABLE_OWNER_MODULE_ALL = 8
# for storing socket info python style.
class socket_info:
State = None
LocalAddr = None
LocalPort = None
RemoteAddr = None
RemotePort = None
def __init__ (self, **kwargs):
for key, word in kwargs.items():
setattr(self, key, word)
def formatip (ip):
ip = inet_aton (str(ip))
return inet_ntoa (ip[::-1])
states = {
1 : "TCP_STATE_CLOSED",
2 : "TCP_STATE_LISTEN",
3 : "TCP_STATE_SYN_SENT",
4 : "TCP_STATE_SYN_RCVD",
5 : "TCP_STATE_ESTAB",
6 : "TCP_STATE_FIN_WAIT",
7 : "TCP_STATE_FIN_WAIT2",
8 : "TCP_STATE_CLOSE_WAIT",
9 : "TCP_STATE_CLOSING",
10 : "TCP_STATE_LAST_ACK",
11 : "TCP_STATE_TIME_WAIT",
12 : "TCP_STATE_DELETE_TCB",
"TCP_STATE_CLOSED" : 1,
"TCP_STATE_LISTEN" : 2,
"TCP_STATE_SYN_SENT" : 3,
"TCP_STATE_SYN_RCVD" : 4,
"TCP_STATE_ESTAB" : 5,
"TCP_STATE_FIN_WAIT" : 6,
"TCP_STATE_FIN_WAIT2" : 7,
"TCP_STATE_CLOSE_WAIT" : 8,
"TCP_STATE_CLOSING" : 9,
"TCP_STATE_LAST_ACK" :10,
"TCP_STATE_TIME_WAIT" : 11,
"TCP_STATE_DELETE_TCB" : 12 }
class MIB_TCPROW_OWNER_PID(Structure):
_fields_ = [
("dwState", DWORD),
("dwLocalAddr", DWORD),
("dwLocalPort", DWORD),
("dwRemoteAddr", DWORD),
("dwRemotePort", DWORD),
("dwOwningPid", DWORD)
]
class MIB_TCPTABLE_OWNER_PID(Structure):
_fields_ = [
("dwNumEntries", DWORD),
("MIB_TCPROW_OWNER_PID", MIB_TCPROW_OWNER_PID * 100)
]
def GetExtendedTcpTable (vip=AF_INET):
table = MIB_TCPTABLE_OWNER_PID ()
so = sizeof (table)
size = DWORD (so)
order = c_int(1)
failure= windll.iphlpapi.GetExtendedTcpTable (
byref (table),
addressof (size),
order,
vip,
TCP_TABLE_OWNER_PID_ALL,
0 )
assert not failure, WinError (GetLastError ())
pytables = []
tables = table.MIB_TCPROW_OWNER_PID
for index in range(table.dwNumEntries):
table = tables [index]
pytables.append (
socket_info (
State=states.get (table.dwState, "UNKNOWN_STATE_%s" %(str(table.dwState))),
LocalAddr=formatip (table.dwLocalAddr),
LocalPort=htons(table.dwLocalPort),
RemoteAddr=formatip (table.dwRemoteAddr),
RemotePort=htons(table.dwRemotePort),
OwningPid = int (table.dwOwningPid)
)
)
return pytables
def GetTcpTableForPid (pid):
tables = GetExtendedTcpTable ()
for table in tables:
if table.OwningPid == pid: return table
raise "Cannot find tcp table for pid %s" %pid
dict_process = {}
pid_set =set()
pid_list = []
tcp_info_list = []
tcp_info = GetExtendedTcpTable()
for item in tcp_info:
LocalAddr = item.LocalAddr
LocalPort = item.LocalPort
RemoteAddr = item.RemoteAddr
RemotePort = item.RemotePort
OwningPid = item.OwningPid
print('local Addr: '+ LocalAddr,'local port: '+ str(LocalPort),'remote Addr: ' + RemoteAddr, 'Remote Port: ' + str(RemotePort), OwningPid)
The script is run from time to time. It can run for 5 minutes and then don't work about an hour with this stupid mistake. How to get around it?
I really dont know, what's with it. Please, help me, what i do wrong?
I use python 3.2 on Win7 SP1 x64
Thank you a lot!
You shouldn't use addressof(size). That returns a Python integer which will be cast as a 32-bit C int. Use byref(size) to create a pointer, which will be a 64-bit value if you're using 64-bit Python.
GetExtendedTcpTable doesn't call SetLastError. It returns a DWORD with one of the following codes:
NO_ERROR = 0
ERROR_INVALID_PARAMETER = 87
ERROR_INSUFFICIENT_BUFFER = 122
The pdwSize argument has the required size if the buffer was too small. One option here is to start with a length 0 array; then resize the struct; and finally cast the array to the correct size:
class MIB_TCPTABLE_OWNER_PID(Structure):
_fields_ = [
("dwNumEntries", DWORD),
("MIB_TCPROW_OWNER_PID", MIB_TCPROW_OWNER_PID * 0),
]
_GetExtendedTcpTable = windll.iphlpapi.GetExtendedTcpTable
def GetExtendedTcpTable(vip=AF_INET):
table = MIB_TCPTABLE_OWNER_PID()
size = DWORD()
order = 1
failure = _GetExtendedTcpTable(
byref(table),
byref(size),
order,
vip,
TCP_TABLE_OWNER_PID_ALL,
0)
if failure == ERROR_INSUFFICIENT_BUFFER:
resize(table, size.value)
memset(byref(table), 0, sizeof(table))
failure = _GetExtendedTcpTable(
byref(table),
byref(size),
order,
vip,
TCP_TABLE_OWNER_PID_ALL,
0)
if failure:
raise WinError(failure)
ptr_type = POINTER(MIB_TCPROW_OWNER_PID * table.dwNumEntries)
tables = cast(table.MIB_TCPROW_OWNER_PID, ptr_type)[0]
pytables = []
for table in tables:
# rest unchanged
Regarding the Win32 LastError value, in general you shouldn't rely on GetLastError in Python. You don't know if you're seeing an old error code from a previous call or if an intervening call modified the LastError value. If you're checking a single API call that uses LastError, then it should be OK to check GetLastError immediately afterward if the call failed. But more generally you may need to load the DLL with use_last_error=True:
iphlpapi = WinDLL('iphlpapi', use_last_error=True)
Function pointers created from this WinDLL instance will save LastError to thread local storage immediately after the call returns. Calling get_last_error returns the saved error code. Beforehand you can call set_last_error(0) to have 0 swapped in to LastError before the function is called.

Multiplex address and data to show string of letters over parallel port

A month ago, i asked this about multiplexing a string of numbers with 4 7-segment displays. But now, I'm trying to update the code to multiplex a string of letters using 7 7-segment displays in python.
This is the new circuit. When i send data using the parallel port, the Latch Enable receives the most significant bit (pin 9). In the second latch, the Latch Enable receives it also but negated, that is the reason of the 7404.
That is either address is set (/LE==False) or data is set (/LE=True).
This is what I'm trying to do. The 'X' represents that the 7-segment display is off. But can't archive it.
XXXXXXX
XXXXXXS
XXXXXST
XXXXSTA
XXXSTAC
XXSTACK
XSTACKX
STACKX0
TACKX0V
ACKX0V3
CKX0V3R
KX0V3RF
X0VERFL
0VERFL0
VERFL0W
ERFL0WX
RFL0WXX
FL0WXXX
L0WXXXX
0WXXXXX
WXXXXXX
XXXXXXX
That would be the output for the string "STACK 0V3RFL0W".
Also the past code:
import sys
import parallel
class Display(object):
def __init__(self):
'''Init and blank the "display".'''
self.display = [' '] * 4
self._update()
def setData(self,data):
'''Bits 0-3 are the "value".
Bits 4-7 are positions 0-3 (first-to-last).
'''
self.display = [' '] * 4
value = data & 0xF
if data & 0x10:
self.display[0] = str(value)
if data & 0x20:
self.display[1] = str(value)
if data & 0x40:
self.display[2] = str(value)
if data & 0x80:
self.display[3] = str(value)
self._update()
def _update(self):
'''Write over the same four terminal positions each time.'''
sys.stdout.write(''.join(self.display) + '\r')
if __name__ == '__main__':
p = Display()
pp=parallel.Parallel()
nums = raw_input("Enter a string of numbers: ")
# Shift over the steam four-at-a-time.
stream = 'XXXX' + nums + 'XXXX'
data = [0] * 4
for i in range(len(stream)-3):
# Precompute data
for pos in range(4):
value = stream[i+pos]
data[pos] = 0 if value == 'X' else (1<<(pos+4)) + int(value)
# "Flicker" the display...
for delay in xrange(1000):
# Display each position briefly.
for d in data:
pp.setData(d)
# Clear the display when done
p.setData(0)
Algorithm outline:
string = "07831505"
while True:
for i in range(7):
# switch display `i` on
notlatch.set(True)
data.set(1 << i)
notlatch.set(False)
time.sleep(<very little>)
notlatch.set(True)
# display character on display `i`
data.set(char_to_7segment(string[i]))
time.sleep(0.01)

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