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Counter is a container included in the collections module.

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This approach requires prior knowledge of total number of iterations.

# A C-style way of accessing list elements
cars = ["Aston", "Audi", "McLaren"]
i = 0
while (i < len(cars)):
    print cars[i]
    i += 1

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By default python’s print() function ends with a newline.

Python’s print() function comes with a parameter called ‘end’.

By default, the value of this parameter is ‘\n’, i.e. the new line character. You can end a print statement with any character/string using this parameter.

# This Python program must be run with
# Python 3 as it won't work with 2.7.
 

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We use two operators * (for tuples) and ** (for dictionaries).

Background

# A Python program to demonstrate need 
# of packing and unpacking
 
# A sample function that takes 4 arguments
# and prints them.
def fun(a, b, c, d):

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Transpose of a matrix is a task we all can perform very easily in python (Using a nested loop). But there are some interesting ways to do the same in a single line.

Matrix

In Python, we can implement a matrix as nested list (list inside a list).

Each element is treated as a row of the matrix.

For example m = [[1, 2], [4, 5], [3, 6]] represents a matrix of 3 rows and 2 columns. First element of the list – m[0] and element in first row, first column – m[0][0].

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Django Lineage

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Django Tutorial Part 5: 主页构建

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Python3爬虫（一）抓取网页的html

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Contents Creating forms from models ModelForm Field types A full example Validation on a ModelForm Overriding the clean() method Interaction with model validation Considerations regarding model’s error_messages The save() method

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• Formsets
  • Using initial data with a formset
  • Limiting the maximum number of forms
  • Formset validation
  • Validating the number of forms in a formset
  • Dealing with ordering and deletion of forms
  • Adding additional fields to a formset
  • Passing custom parameters to formset forms
  • Customizing a formset’s prefix
  • Using a formset in views and templates