unicode转换成string★python字符串内置功能(2)

1 >>> str = "programmer"
2 >>> sub = "Python" 3 >>> print('I am a {}, and learn {}'.format(str,sub)) 4 I am a programmer, and learn Python 5 >>> print('I am a {1}, and learn {0}'.format(str,sub)) 6 I am a Python, and learn programmer 7 >>> print('I am a {name}, and learn {tool}'.format(name = str,tool = sub)) 8 I am a programmer, and learn Python

str.format_map(mapping) --> String执行字符串格式化操作，替换字段使用{}分隔，同str.format(**mapping), 除了直接使用mapping，而不复制到一个dict

1 >>> name = "Peter"
2 >>> country = "China" 3 >>> print('I\'m {name} and bron in {country}.'.format_map(vars())) 4 I'm Peter and bron in China. 5 6 >>> str = "programmer" 7 >>> sub = "Python" 8 >>> print('I am a {str}, and learnning {sub}.'.format_map(vars())) 9 I am a programmer, and learn Python.

注： 此方法 出于 Python 3.2 之后

str.index(sub[,start[,end]]) --> int检测字符串string中是否包含子字符串sub，如果存在，则返回sub在string中的索引值(下标)，如果指定began（开始）和end（结束）范围，则检查是否包含在指定范围内，该方法与pythonfind()方法一样，只不过如果str不在string中会报一个异常(ValueError:substringnotfound)。

>>> str = "programmer"
>>> print(str.index('m'))
6
>>> print(str.index('m',6,9)) 6 >>> print(str.index('m',7,9)) 7

str.isalnum() --> Bool (True or False)判断字符串String是否由字符串或数字组成，并且至少有一个字符（不为空）简而言之：只要c.isalpha(),c.isdecimal(),c.isdigit(),c.isnumeric()中任意一个为真，则c.isalnum()为真。

'dobi'.isalnum()
# True
'dobi123'.isalnum()
# True
'123'.isalnum()
# True
'张'.isalnum()
# True
'dobi_123'.isalnum()
# False
'dobi 123'.isalnum()
# False
'%'.isalnum()
# False

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