go string

• 字符串替换:

  strings.Replace(str string, old string, new string, n int)

• 字符串计数:

  strings.Count(str string, substr string)int

• 重复count次str:

  strings.Repeat(str string, count int)string

• 转为小写:

  strings.ToLower(str string)string

• 转为大写:

  strings.ToUpper(str string)string