python中的printf：%號拼接字符串和format函數

在C語言中，我們使用printf("%s","hello")這種形式進行字符串的拼接

在python中，進行這樣的拼接有兩種實現方式，分別是%號拼接以及使用format函數，以下進行代碼演示

%號拼接字符串

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 在python中是用%號可以進行字符串的拼接，這個跟print函數是無關的。以下進行舉例

• 打印字符串

  msg = "i am %s,my blogs is %s" % ("CodeScrew","www.cnblogs.com/codescrew")
  print(msg)

• 打印浮點數

  msg = "i am %0.2f m" %1.785
  print(msg)  #打印結果為i am 1.78 m

  其中%號后面的.2表示保留2位小數

• 打印百分比

  msg = "it is %0.2f %%" % 99.852
  print(msg)  #打印結果為it is 99.85 %

• 使用鍵值對進行拼接

  msg = "i am %(name)s.my age is %(age)d" % ({"name":"CodeScrew","age":23})
  print(msg)  #打印結果為i am CodeScrew.my age is 23

format函數處理字符串

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 除了%號進行拼接，還可以使用字符串類的format函數，以下列舉了常用的使用。

msg = "i am {},age is {}".format("CodeScrew",23)
print(msg)  #打印結果為i am CodeScrew,age is 23

msg = "i am {1},age is {0}".format("CodeScrew",23)
print(msg)  #打印結果為i am 23,age is CodeScrew

msg = "i am {name},age is {age}".format(name="CodeScrew",age=23)
print(msg)  #打印結果為i am CodeScrew,age is 23

msg = "i am {name},age is {age}".format(**{"name":"CodeScrew","age":23})
print(msg)  #打印結果為i am CodeScrew,age is 23

msg = "i am {:s},age is {:d}".format("CodeScrew",23)
print(msg)  #打印結果為i am CodeScrew,age is 23

msg = "i am {:s},age is {:d}".format(*["CodeScrew",23])
print(msg)  #打印結果為i am CodeScrew,age is 23

msg = "Numbers:{:b},{:o},{:d},{:x},{:X}".format(15,15,15,15,15)
print(msg)  #打印結果為Numbers:1111,17,15,f,F