本帖最后由 gaoyang9992006 于 2019-1-24 23:16 编辑
Here are some samples to help get a better idea of Python's syntax:
Hello World (the traditional first program)
print 'Hello world!' # Python 2 syntax
# or
print('Hello world!') # Python 3 syntax
String formatting
name = 'Monty'
print('Hello, %s' % name) # string interpolation
print('Hello, {}'.format(name)) # string formatting
Defining a function
def add_one(x):
return x + 1
Testing variable equality
x = 1
y = 2
print 'x is equal to y: %s' % (x == y)
z = 1
print 'x is equal to z: %s' % (x == z)
names = ['Donald', 'Jake', 'Phil']
words = ['Random', 'Words', 'Dogs']
if names == words:
print 'Names list is equal to words'
else:
print "Names list isn't equal to words"
new_names = ['Donald', 'Jake', 'Phil']
print 'New names list is equal to names: %s' % (new_names == names)
Defining a class with two methods
class Talker(object):
def greet(self, name):
print 'Hello, %s!' % name
def farewell(self, name):
print 'Farewell, %s!' % name
Defining a list
dynamic_languages = ['Python', 'Ruby', 'Groovy']
dynamic_languages.append('Lisp')
Defining a dictionary
numbered_words = dict()
numbered_words[2] = 'world'
numbered_words[1] = 'Hello'
numbered_words[3] = '!'
Defining a while loop
while True:
if value == wanted_value:
break
else:
pass
Defining multiline strings
string = '''This is a string with embedded newlines.
Also known as a tripled-quoted string.
Whitespace at the beginning of lines is included,
so the above line is indented but the others are not.
'''
Splitting a long string over several lines of source code
string = ('This is a single long, long string'
' written over many lines for convenience'
' using implicit concatenation to join each'
' piece into a single string without extra'
' newlines (unless you add them yourself).')
Defining a for loop
for x in xrange(1, 4):
print ('Hello, new Python user!'
'This is time number %d') % x
List comprehension
l = [x**2 for x in range(4)]
print(l)
# [0, 1, 4, 9]
Set comprehension with condition
squares = {x**2 for x in [0,2,4] if x < 4}
print(squares)
# {0, 4}
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