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Detailed explanation of python3+PyQt5 generic delegation

Apr 24, 2018 am 11:24 AM
entrustDetailed explanation

This article mainly introduces the relevant information of python3 PyQt5 generic delegation to everyone in detail. It has certain reference value. Interested friends can refer to it.

Custom delegation allows us to view the view. Take full control over the appearance and behavior of data items that appear in . If you have a lot of models, you may want to be able to use just one custom delegate for most of the models, but if you can't do that, you will most likely have a lot of duplicate code for those custom delegates. To make maintenance easier, a better approach is not to create a custom delegate for each model, but to use a series of common components that together form a delegate. This article implements the generic delegation example of Chapter 16 of python Qt GUI rapid programming through Python3 pyqt5.

/home/yrd/eric_workspace/chap16/richtextlineedit.py

#!/usr/bin/env python3

import platform
import sys
import html
from PyQt5.QtCore import QSize, Qt,pyqtSignal
from PyQt5.QtGui import QColor, QFont,QFontMetrics, QIcon, QKeySequence, QPixmap,QTextCharFormat
from PyQt5.QtWidgets import QAction,QApplication,QMenu,QTextEdit


class RichTextLineEdit(QTextEdit):
 returnPressed=pyqtSignal()
 (Bold, Italic, Underline, StrikeOut, Monospaced, Sans, Serif,
  NoSuperOrSubscript, Subscript, Superscript) = range(10)


 def __init__(self, parent=None):
  super(RichTextLineEdit, self).__init__(parent)

  self.monofamily = "courier"
  self.sansfamily = "helvetica"
  self.seriffamily = "times"
  self.setLineWrapMode(QTextEdit.NoWrap)
  self.setTabChangesFocus(True)
  self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
  self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
  fm = QFontMetrics(self.font())
  h = int(fm.height() * (1.4 if platform.system() == "Windows"
         else 1.2))
  self.setMinimumHeight(h)
  self.setMaximumHeight(int(h * 1.2))
  self.setToolTip("Press <b>Ctrl+M</b> for the text effects "
    "menu and <b>Ctrl+K</b> for the color menu")


 def toggleItalic(self):
  self.setFontItalic(not self.fontItalic())


 def toggleUnderline(self):
  self.setFontUnderline(not self.fontUnderline())


 def toggleBold(self):
  self.setFontWeight(QFont.Normal
    if self.fontWeight() > QFont.Normal else QFont.Bold)


 def sizeHint(self):
  return QSize(self.document().idealWidth() + 5,
      self.maximumHeight())


 def minimumSizeHint(self):
  fm = QFontMetrics(self.font())
  return QSize(fm.width("WWWW"), self.minimumHeight())


 def contextMenuEvent(self, event):
  self.textEffectMenu()


 def keyPressEvent(self, event):
  if event.modifiers() & Qt.ControlModifier:
   handled = False
   if event.key() == Qt.Key_B:
    self.toggleBold()
    handled = True
   elif event.key() == Qt.Key_I:
    self.toggleItalic()
    handled = True
   elif event.key() == Qt.Key_K:
    self.colorMenu()
    handled = True
   elif event.key() == Qt.Key_M:
    self.textEffectMenu()
    handled = True
   elif event.key() == Qt.Key_U:
    self.toggleUnderline()
    handled = True
   if handled:
    event.accept()
    return
  if event.key() in (Qt.Key_Enter, Qt.Key_Return):
   self.returnPressed.emit()
   event.accept()
  else:
   QTextEdit.keyPressEvent(self, event)


 def colorMenu(self):
  pixmap = QPixmap(22, 22)
  menu = QMenu("Colour")
  for text, color in (
    ("&Black", Qt.black),
    ("B&lue", Qt.blue),
    ("Dark Bl&ue", Qt.darkBlue),
    ("&Cyan", Qt.cyan),
    ("Dar&k Cyan", Qt.darkCyan),
    ("&Green", Qt.green),
    ("Dark Gr&een", Qt.darkGreen),
    ("M&agenta", Qt.magenta),
    ("Dark Mage&nta", Qt.darkMagenta),
    ("&Red", Qt.red),
    ("&Dark Red", Qt.darkRed)):
   color = QColor(color)
   pixmap.fill(color)
   action = menu.addAction(QIcon(pixmap), text, self.setColor)
   action.setData(color)
  self.ensureCursorVisible()
  menu.exec_(self.viewport().mapToGlobal(
     self.cursorRect().center()))


 def setColor(self):
  action = self.sender()
  if action is not None and isinstance(action, QAction):
   color = QColor(action.data())
   if color.isValid():
    self.setTextColor(color)


 def textEffectMenu(self):
  format = self.currentCharFormat()
  menu = QMenu("Text Effect")
  for text, shortcut, data, checked in (
    ("&Bold", "Ctrl+B", RichTextLineEdit.Bold,
     self.fontWeight() > QFont.Normal),
    ("&Italic", "Ctrl+I", RichTextLineEdit.Italic,
     self.fontItalic()),
    ("Strike &out", None, RichTextLineEdit.StrikeOut,
     format.fontStrikeOut()),
    ("&Underline", "Ctrl+U", RichTextLineEdit.Underline,
     self.fontUnderline()),
    ("&Monospaced", None, RichTextLineEdit.Monospaced,
     format.fontFamily() == self.monofamily),
    ("&Serifed", None, RichTextLineEdit.Serif,
     format.fontFamily() == self.seriffamily),
    ("S&ans Serif", None, RichTextLineEdit.Sans,
     format.fontFamily() == self.sansfamily),
    ("&No super or subscript", None,
     RichTextLineEdit.NoSuperOrSubscript,
     format.verticalAlignment() ==
     QTextCharFormat.AlignNormal),
    ("Su&perscript", None, RichTextLineEdit.Superscript,
     format.verticalAlignment() ==
     QTextCharFormat.AlignSuperScript),
    ("Subs&cript", None, RichTextLineEdit.Subscript,
     format.verticalAlignment() ==
     QTextCharFormat.AlignSubScript)):
   action = menu.addAction(text, self.setTextEffect)
   if shortcut is not None:
    action.setShortcut(QKeySequence(shortcut))
   action.setData(data)
   action.setCheckable(True)
   action.setChecked(checked)
  self.ensureCursorVisible()
  menu.exec_(self.viewport().mapToGlobal(
     self.cursorRect().center()))


 def setTextEffect(self):
  action = self.sender()
  if action is not None and isinstance(action, QAction):
   what = action.data()
   if what == RichTextLineEdit.Bold:
    self.toggleBold()
    return
   if what == RichTextLineEdit.Italic:
    self.toggleItalic()
    return
   if what == RichTextLineEdit.Underline:
    self.toggleUnderline()
    return
   format = self.currentCharFormat()
   if what == RichTextLineEdit.Monospaced:
    format.setFontFamily(self.monofamily)
   elif what == RichTextLineEdit.Serif:
    format.setFontFamily(self.seriffamily)
   elif what == RichTextLineEdit.Sans:
    format.setFontFamily(self.sansfamily)
   if what == RichTextLineEdit.StrikeOut:
    format.setFontStrikeOut(not format.fontStrikeOut())
   if what == RichTextLineEdit.NoSuperOrSubscript:
    format.setVerticalAlignment(
      QTextCharFormat.AlignNormal)
   elif what == RichTextLineEdit.Superscript:
    format.setVerticalAlignment(
      QTextCharFormat.AlignSuperScript)
   elif what == RichTextLineEdit.Subscript:
    format.setVerticalAlignment(
      QTextCharFormat.AlignSubScript)
   self.mergeCurrentCharFormat(format)


 def toSimpleHtml(self):
  htmltext = ""
  black = QColor(Qt.black)
  block = self.document().begin()
  while block.isValid():
   iterator = block.begin()
   while iterator != block.end():
    fragment = iterator.fragment()
    if fragment.isValid():
     format = fragment.charFormat()
     family = format.fontFamily()
     color = format.foreground().color()     
     text=html.escape(fragment.text())
     if (format.verticalAlignment() ==
      QTextCharFormat.AlignSubScript):
      text = "<sub>{0}</sub>".format(text)
     elif (format.verticalAlignment() ==
       QTextCharFormat.AlignSuperScript):
      text = "<sup>{0}</sup>".format(text)
     if format.fontUnderline():
      text = "<u>{0}</u>".format(text)
     if format.fontItalic():
      text = "<i>{0}</i>".format(text)
     if format.fontWeight() > QFont.Normal:
      text = "<b>{0}</b>".format(text)
     if format.fontStrikeOut():
      text = "<s>{0}</s>".format(text)
     if color != black or family:
      attribs = ""
      if color != black:
       attribs += &#39; color="{0}"&#39;.format(color.name())
      if family:
       attribs += &#39; face="{0}"&#39;.format(family)
      text = "<font{0}>{1}</font>".format(attribs,text)
     htmltext += text
    iterator += 1
   block = block.next()
  return htmltext

if __name__ == "__main__":
 def printout(lineedit):
  print(str(lineedit.toHtml()))
  print(str(lineedit.toPlainText()))
  print(str(lineedit.toSimpleHtml()))    
 app = QApplication(sys.argv)
 lineedit = RichTextLineEdit()
 lineedit.returnPressed.connect(lambda:printout(lineedit))
 lineedit.show()
 lineedit.setWindowTitle("RichTextEdit")
 app.exec_()

/home/yrd/eric_workspace/chap16/genericdelegates .py


#!/usr/bin/env python3

from PyQt5.QtCore import (QDate, QSize, Qt)
from PyQt5.QtWidgets import (QApplication, QDateEdit, QLineEdit,
  QSpinBox, QStyledItemDelegate,QStyle)
from PyQt5.QtGui import QColor,QTextDocument
import richtextlineedit


class GenericDelegate(QStyledItemDelegate):

 def __init__(self, parent=None):
  super(GenericDelegate, self).__init__(parent)
  self.delegates = {}


 def insertColumnDelegate(self, column, delegate):
  delegate.setParent(self)
  self.delegates[column] = delegate


 def removeColumnDelegate(self, column):
  if column in self.delegates:
   del self.delegates[column]


 def paint(self, painter, option, index):
  delegate = self.delegates.get(index.column())
  if delegate is not None:
   delegate.paint(painter, option, index)
  else:
   QStyledItemDelegate.paint(self, painter, option, index)


 def createEditor(self, parent, option, index):
  delegate = self.delegates.get(index.column())
  if delegate is not None:
   return delegate.createEditor(parent, option, index)
  else:
   return QStyledItemDelegate.createEditor(self, parent, option,
             index)


 def setEditorData(self, editor, index):
  delegate = self.delegates.get(index.column())
  if delegate is not None:
   delegate.setEditorData(editor, index)
  else:
   QStyledItemDelegate.setEditorData(self, editor, index)


 def setModelData(self, editor, model, index):
  delegate = self.delegates.get(index.column())
  if delegate is not None:
   delegate.setModelData(editor, model, index)
  else:
   QStyledItemDelegate.setModelData(self, editor, model, index)


class IntegerColumnDelegate(QStyledItemDelegate):

 def __init__(self, minimum=0, maximum=100, parent=None):
  super(IntegerColumnDelegate, self).__init__(parent)
  self.minimum = minimum
  self.maximum = maximum


 def createEditor(self, parent, option, index):
  spinbox = QSpinBox(parent)
  spinbox.setRange(self.minimum, self.maximum)
  spinbox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
  return spinbox


 def setEditorData(self, editor, index):
  value = index.model().data(index, Qt.DisplayRole)
  editor.setValue(value)


 def setModelData(self, editor, model, index):
  editor.interpretText()
  model.setData(index, editor.value())


class DateColumnDelegate(QStyledItemDelegate):

 def __init__(self, minimum=QDate(),
     maximum=QDate.currentDate(),
     format="yyyy-MM-dd", parent=None):
  super(DateColumnDelegate, self).__init__(parent)
  self.minimum = minimum
  self.maximum = maximum
  self.format = format


 def createEditor(self, parent, option, index):
  dateedit = QDateEdit(parent)
  #dateedit=QDateTimeEdit(parent)
  dateedit.setDateRange(self.minimum, self.maximum)
  dateedit.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
  dateedit.setDisplayFormat(self.format)
  dateedit.setCalendarPopup(True)
  return dateedit


 def setEditorData(self, editor, index):
  value = index.model().data(index, Qt.DisplayRole)
  #if value.isNull:
  editor.setDate(value)
  #editor.setDisplayFormat(self.format)

 def setModelData(self, editor, model, index):
  model.setData(index, editor.date())
 def paint(self, painter, option, index):
  text = index.model().data(index, Qt.DisplayRole).toString(self.format)
  palette = QApplication.palette()
  document = QTextDocument()
  document.setDefaultFont(option.font)
  if option.state & QStyle.State_Selected:
   document.setHtml("<font color={0}>{1}</font>".format(palette.highlightedText().color().name(),text))
  else:
   document.setHtml(text)
  painter.save()
  color = (palette.highlight().color()
     if option.state & QStyle.State_Selected
     else QColor(index.model().data(index,
        Qt.BackgroundColorRole)))
  painter.fillRect(option.rect, color)
  painter.translate(option.rect.x(), option.rect.y())
  document.drawContents(painter)
  painter.restore()  


class PlainTextColumnDelegate(QStyledItemDelegate):

 def __init__(self, parent=None):
  super(PlainTextColumnDelegate, self).__init__(parent)


 def createEditor(self, parent, option, index):
  lineedit = QLineEdit(parent)
  return lineedit


 def setEditorData(self, editor, index):
  value = index.model().data(index, Qt.DisplayRole)
  editor.setText(value)


 def setModelData(self, editor, model, index):
  model.setData(index, editor.text())


class RichTextColumnDelegate(QStyledItemDelegate):

 def __init__(self, parent=None):
  super(RichTextColumnDelegate, self).__init__(parent)


 def paint(self, painter, option, index):
  text = index.model().data(index, Qt.DisplayRole)
  palette = QApplication.palette()
  document = QTextDocument()
  document.setDefaultFont(option.font)
  if option.state & QStyle.State_Selected:
   document.setHtml("<font color={0}>{1}</font>".format(palette.highlightedText().color().name(),text))
  else:
   document.setHtml(text)
  painter.save()
  color = (palette.highlight().color()
     if option.state & QStyle.State_Selected
     else QColor(index.model().data(index,
        Qt.BackgroundColorRole)))
  painter.fillRect(option.rect, color)
  painter.translate(option.rect.x(), option.rect.y())
  document.drawContents(painter)
  painter.restore()


 def sizeHint(self, option, index):
  text = index.model().data(index).toString()
  document = QTextDocument()
  document.setDefaultFont(option.font)
  document.setHtml(text)
  return QSize(document.idealWidth() + 5,
      option.fontMetrics.height())


 def createEditor(self, parent, option, index):
  lineedit = richtextlineedit.RichTextLineEdit(parent)
  return lineedit


 def setEditorData(self, editor, index):
  value = index.model().data(index, Qt.DisplayRole)
  editor.setHtml(value)


 def setModelData(self, editor, model, index):
  model.setData(index, editor.toSimpleHtml())

/home/yrd/eric_workspace/chap16/carhirelog.pyw


#!/usr/bin/env python3

import bisect
import os
import platform
import sys
from PyQt5.QtCore import (QAbstractTableModel, QDate, QModelIndex,
  QVariant, Qt,pyqtSignal)
from PyQt5.QtWidgets import (QApplication, QMainWindow,
  QShortcut, QTableView)
from PyQt5.QtGui import QKeySequence
import genericdelegates


(LICENSE, CUSTOMER, HIRED, MILEAGEOUT, RETURNED, MILEAGEBACK,
 NOTES, MILEAGE, DAYS) = range(9)


class CarHireLog(object):

 def __init__(self, license, customer, hired, mileageout,
     returned=QDate(), mileageback=0, notes=""):
  self.license = license  # plain text
  self.customer = customer # plain text
  self.hired = hired     # QDate
  self.mileageout = mileageout   # int
  self.returned = returned    # QDate
  self.mileageback = mileageback  # int
  self.notes = notes   # HTML


 def field(self, column):
  if column == LICENSE:
   return self.license
  elif column == CUSTOMER:
   return self.customer
  elif column == HIRED:
   return self.hired
  elif column == MILEAGEOUT:
   return self.mileageout
  elif column == RETURNED:
   return self.returned
  elif column == MILEAGEBACK:
   return self.mileageback
  elif column == NOTES:
   return self.notes
  elif column == MILEAGE:
   return self.mileage()
  elif column == DAYS:
   return self.days()
  assert False


 def mileage(self):
  return (0 if self.mileageback == 0
     else self.mileageback - self.mileageout)


 def days(self):
  return (0 if not self.returned.isValid()
     else self.hired.daysTo(self.returned))


 def __hash__(self):
  return super(CarHireLog, self).__hash__()


 def __eq__(self, other):
  if self.hired != other.hired:
   return False
  if self.customer != other.customer:
   return False
  if self.license != other.license:
   return False
  return id(self) == id(other)


 def __lt__(self, other):
  if self.hired < other.hired:
   return True
  if self.customer < other.customer:
   return True
  if self.license < other.license:
   return True
  return id(self) < id(other)


class CarHireModel(QAbstractTableModel):
 dataChanged = pyqtSignal(QModelIndex,QModelIndex)
 def __init__(self, parent=None):
  super(CarHireModel, self).__init__(parent)
  self.logs = []

  # Generate fake data
  import gzip
  import random
  import string
  surname_data = gzip.open(os.path.join(
    os.path.dirname(__file__), "surnames.txt.gz")).read()
  surnames = surname_data.decode("utf8").splitlines()
  years = ("06 ", "56 ", "07 ", "57 ", "08 ", "58 ")
  titles = ("Ms ", "Mr ", "Ms ", "Mr ", "Ms ", "Mr ", "Dr ")
  notetexts = ("Returned <font color=red><b>damaged</b></font>",
    "Returned with <i>empty fuel tank</i>",
    "Customer <b>complained</b> about the <u>engine</u>",
    "Customer <b>complained</b> about the <u>gears</u>",
    "Customer <b>complained</b> about the <u>clutch</u>",
    "Returned <font color=darkred><b>dirty</b></font>",)
  today = QDate.currentDate()
  for i in range(250):
   license = []
   for c in range(5):
    license.append(random.choice(string.ascii_uppercase))
   license = ("".join(license[:2]) + random.choice(years) +
      "".join(license[2:]))
   customer = random.choice(titles) + random.choice(surnames)
   hired = today.addDays(-random.randint(0, 365))
   mileageout = random.randint(10000, 30000)
   notes = ""
   if random.random() >= 0.2:
    days = random.randint(1, 21)
    returned = hired.addDays(days)
    mileageback = (mileageout +
        (days * random.randint(30, 300)))
    if random.random() > 0.75:
     notes = random.choice(notetexts)
   else:
    returned = QDate()
    mileageback = 0
   log = CarHireLog(license, customer, hired, mileageout,
        returned, mileageback, notes)
   bisect.insort(self.logs, log)


 def rowCount(self, index=QModelIndex()):
  return len(self.logs)


 def columnCount(self, index=QModelIndex()):
  return 9


 def data(self, index, role):
  if not index.isValid():
   return QVariant()
  if role == Qt.DisplayRole:
   log = self.logs[index.row()]
   value = log.field(index.column())
   if (index.column() in (MILEAGEBACK, MILEAGE, DAYS) and
    value == 0):
    return 0
   return value
  if (role == Qt.TextAlignmentRole and
   index.column() not in (LICENSE, CUSTOMER, NOTES)):
   return QVariant(int(Qt.AlignRight|Qt.AlignVCenter))
  if role == Qt.BackgroundColorRole:
   palette = QApplication.palette()
   if index.column() in (LICENSE, MILEAGE, DAYS):
    return QVariant(palette.alternateBase())
   else:
    return QVariant(palette.base())
  return QVariant()


 def setData(self, index, value, role=Qt.EditRole):
  if (index.isValid() and role == Qt.EditRole and
   index.column() not in (LICENSE, MILEAGE, DAYS)):
   log = self.logs[index.row()]
   column = index.column()
   if column == CUSTOMER:
    log.customer = value
   elif column == HIRED:
    #log.hired = value.toDate()
    log.hired = value
   elif column == MILEAGEOUT:
    log.mileageout = value
   elif column == RETURNED:
    #log.returned = value.toDate()
    log.returned = value
   elif column == MILEAGEBACK:
    log.mileageback = value
   elif column == NOTES:
    log.notes = value
   self.dataChanged[QModelIndex,QModelIndex].emit(index,index)
   return True
  return False


 def headerData(self, section, orientation, role):
  if role == Qt.TextAlignmentRole:
   if orientation == Qt.Horizontal:
    return QVariant(int(Qt.AlignCenter))
   return QVariant(int(Qt.AlignRight|Qt.AlignVCenter))
  if role != Qt.DisplayRole:
   return QVariant()
  if orientation == Qt.Horizontal:
   if section == LICENSE:
    return "License"
   elif section == CUSTOMER:
    return "Customer"
   elif section == HIRED:
    return "Hired"
   elif section == MILEAGEOUT:
    return "Mileage #1"
   elif section == RETURNED:
    return "Returned"
   elif section == MILEAGEBACK:
    return "Mileage #2"
   elif section == DAYS:
    return "Days"
   elif section == MILEAGE:
    return "Miles"
   elif section == NOTES:
    return "Notes"
  return section + 1


 def flags(self, index):
  flag = QAbstractTableModel.flags(self, index)
  if index.column() not in (LICENSE, MILEAGE, DAYS):
   flag |= Qt.ItemIsEditable
  return flag


class HireDateColumnDelegate(genericdelegates.DateColumnDelegate):

 def createEditor(self, parent, option, index):
  i = index.sibling(index.row(), RETURNED)
  self.maximum = i.model().data(i, Qt.DisplayRole).addDays(-1)
  return genericdelegates.DateColumnDelegate.createEditor(
    self, parent, option, index)


class ReturnDateColumnDelegate(genericdelegates.DateColumnDelegate):

 def createEditor(self, parent, option, index):
  i = index.sibling(index.row(), HIRED)
  self.minimum = i.model().data(i, Qt.DisplayRole).addDays(1)
  return genericdelegates.DateColumnDelegate.createEditor(
    self, parent, option, index)


class MileageOutColumnDelegate(genericdelegates.IntegerColumnDelegate):

 def createEditor(self, parent, option, index):
  i = index.sibling(index.row(), MILEAGEBACK)
  maximum = i.model().data(i, Qt.DisplayRole)
  self.maximum = 1000000 if maximum == 0 else maximum - 1
  return genericdelegates.IntegerColumnDelegate.createEditor(
    self, parent, option, index)


class MileageBackColumnDelegate(genericdelegates.IntegerColumnDelegate):

 def createEditor(self, parent, option, index):
  i = index.sibling(index.row(), MILEAGEOUT)
  self.minimum = i.model().data(i, Qt.DisplayRole) + 1
  return genericdelegates.IntegerColumnDelegate.createEditor(
    self, parent, option, index)


class MainForm(QMainWindow):

 def __init__(self, parent=None):
  super(MainForm, self).__init__(parent)

  model = CarHireModel(self)

  self.view = QTableView()
  self.view.setModel(model)
  self.view.resizeColumnsToContents()

  delegate = genericdelegates.GenericDelegate(self)
  delegate.insertColumnDelegate(CUSTOMER,
    genericdelegates.PlainTextColumnDelegate())
  earliest = QDate.currentDate().addYears(-3)
  delegate.insertColumnDelegate(HIRED,
    HireDateColumnDelegate(earliest))
  delegate.insertColumnDelegate(MILEAGEOUT,
    MileageOutColumnDelegate(0, 1000000))
  delegate.insertColumnDelegate(RETURNED,
    ReturnDateColumnDelegate(earliest))
  delegate.insertColumnDelegate(MILEAGEBACK,
    MileageBackColumnDelegate(0, 1000000))
  delegate.insertColumnDelegate(NOTES,
    genericdelegates.RichTextColumnDelegate())

  self.view.setItemDelegate(delegate)
  self.setCentralWidget(self.view)

  QShortcut(QKeySequence("Escape"), self, self.close)
  QShortcut(QKeySequence("Ctrl+Q"), self, self.close)

  self.setWindowTitle("Car Hire Logs")


app = QApplication(sys.argv)
form = MainForm()
rect = QApplication.desktop().availableGeometry()
form.resize(int(rect.width() * 0.7), int(rect.height() * 0.8))
form.move(0, 0)
form.show()
app.exec_()

Running results:

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Python is easier to learn and use, while C is more powerful but complex. 1. Python syntax is concise and suitable for beginners. Dynamic typing and automatic memory management make it easy to use, but may cause runtime errors. 2.C provides low-level control and advanced features, suitable for high-performance applications, but has a high learning threshold and requires manual memory and type safety management.

Python vs. C  : Memory Management and ControlPython vs. C : Memory Management and ControlApr 19, 2025 am 12:17 AM

Python and C have significant differences in memory management and control. 1. Python uses automatic memory management, based on reference counting and garbage collection, simplifying the work of programmers. 2.C requires manual management of memory, providing more control but increasing complexity and error risk. Which language to choose should be based on project requirements and team technology stack.

Python for Scientific Computing: A Detailed LookPython for Scientific Computing: A Detailed LookApr 19, 2025 am 12:15 AM

Python's applications in scientific computing include data analysis, machine learning, numerical simulation and visualization. 1.Numpy provides efficient multi-dimensional arrays and mathematical functions. 2. SciPy extends Numpy functionality and provides optimization and linear algebra tools. 3. Pandas is used for data processing and analysis. 4.Matplotlib is used to generate various graphs and visual results.

Python and C  : Finding the Right ToolPython and C : Finding the Right ToolApr 19, 2025 am 12:04 AM

Whether to choose Python or C depends on project requirements: 1) Python is suitable for rapid development, data science, and scripting because of its concise syntax and rich libraries; 2) C is suitable for scenarios that require high performance and underlying control, such as system programming and game development, because of its compilation and manual memory management.

Python for Data Science and Machine LearningPython for Data Science and Machine LearningApr 19, 2025 am 12:02 AM

Python is widely used in data science and machine learning, mainly relying on its simplicity and a powerful library ecosystem. 1) Pandas is used for data processing and analysis, 2) Numpy provides efficient numerical calculations, and 3) Scikit-learn is used for machine learning model construction and optimization, these libraries make Python an ideal tool for data science and machine learning.

Learning Python: Is 2 Hours of Daily Study Sufficient?Learning Python: Is 2 Hours of Daily Study Sufficient?Apr 18, 2025 am 12:22 AM

Is it enough to learn Python for two hours a day? It depends on your goals and learning methods. 1) Develop a clear learning plan, 2) Select appropriate learning resources and methods, 3) Practice and review and consolidate hands-on practice and review and consolidate, and you can gradually master the basic knowledge and advanced functions of Python during this period.

Python for Web Development: Key ApplicationsPython for Web Development: Key ApplicationsApr 18, 2025 am 12:20 AM

Key applications of Python in web development include the use of Django and Flask frameworks, API development, data analysis and visualization, machine learning and AI, and performance optimization. 1. Django and Flask framework: Django is suitable for rapid development of complex applications, and Flask is suitable for small or highly customized projects. 2. API development: Use Flask or DjangoRESTFramework to build RESTfulAPI. 3. Data analysis and visualization: Use Python to process data and display it through the web interface. 4. Machine Learning and AI: Python is used to build intelligent web applications. 5. Performance optimization: optimized through asynchronous programming, caching and code

Python vs. C  : Exploring Performance and EfficiencyPython vs. C : Exploring Performance and EfficiencyApr 18, 2025 am 12:20 AM

Python is better than C in development efficiency, but C is higher in execution performance. 1. Python's concise syntax and rich libraries improve development efficiency. 2.C's compilation-type characteristics and hardware control improve execution performance. When making a choice, you need to weigh the development speed and execution efficiency based on project needs.

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