190322字符串

一、字符串拼接

1、百分号的使用方法

• %s 字符串
• %d 整数
• %.2f 浮点数，默认保留6位小数，超出位四舍五入
• %% 打印百分号
• %(KEY)s 接收字典

msg1 = "My name is %s." % "dongfei"
print(msg1)  #My name is dongfei

msg2 = "My name is %s, %d years old this year." % ("dongfei", 18)
print(msg2)  #My name is dongfei, 18 years old this year

msg3 = "pai is %.6f" % 3.1415926
print(msg3)  #pai is 3.141593

msg4 = "%.2f %%" % 99.99
print(msg4)  #99.99 %

msg5 = "My name is %(name)s, %(age)d years old this year." % {"name": "dongfei", "age": 18}
print(msg5)  #My name is dongfei, 18 years old this year.

• print() 分隔符

print("root", "x", "0", sep=":")  #root:x:0

2、Format方法

msg6 = "My name is {}, {} years old this year.".format("dongfei", 18)
print(msg6)  #My name is dongfei, 18 years old this year.

msg7 = "My name is {1}, {0} years old this year.".format("dongfei", 18)
print(msg7)  #My name is 18, dongfei years old this year.

msg8 = "My name is {name}, {age} years old this year.".format(name="dongfei", age=18)
print(msg8)  #My name is dongfei, 18 years old this year.

msg9 = "My name is {name}, {age} years old this year.".format(**{"name":"dongfei", "age":18})
print(msg9)  #My name is dongfei, 18 years old this year.

msg10 = "My name is {:s}, {:d} years old this year.".format("dongfei", 18)
print(msg10)  #My name is dongfei, 18 years old this year.

msg11 = "My name is {:s}, {:d} years old this year.".format(*["dongfei", 18])
print(msg11)  #My name is dongfei, 18 years old this year.

msg12 = "My name is {name:s}, {age:d} years old this year.".format(**{"name":"dongfei", "age":18})
print(msg12)  #My name is dongfei, 18 years old this year.

msg13 = "numbers: {:b},{:o},{:d},{:x},{:X}, {:%}".format(15, 15, 15, 15, 15, 15.87623, 2)  #b 二进制，o 八进制，d 十进制，x 十六进制(小写)，X 十六进制(大写)，% 百分百 默认小数点后保留6位
print(msg13)  #numbers: 1111,17,15,f,F, 1587.623000%