python中格式化输出和字母大小写转换，对齐填充方式

#格式化输出print("ang is a good time")str7="ong is a boy"num=10f=5.22313# %d(整数站位符)  %s(字符串站位符)  %f(浮点数站位符)#  %f默认小数点后6位，%.3f精确到小数点后3位。默认会四舍五入print("num=",num,"f=",f)print("num= %d，str7=%s,f=%.9f" %(num,str7,f))‘‘‘#转义字符  \将一些字符转换成有特殊含义的字符‘‘‘# \n换行符，print("num= %d\nstr7=%s\nf=%.9f" %(num,str7,f))print("ong is a good \team")#显示ong is a good \team#如果要没特殊含义出现都是两\\出现的print("ong is a good \\n team")#ong is a good \n team#  \‘  \"  避免单引号中还有引号出现错误#print(‘tom is a ‘good‘man‘)#这样会报出print(‘tom is a \‘good\‘man‘)print("tom is a ‘good‘man")#双引号里面可以有单引号print("tom is a \"good\"man")#如果多行转换可以用3个单引号或者3个双引号print("""ongisgoodteam""")#   \t  制表符 是4个空格print("tom\t girl")#如果字符中有很多字符串都需要转义，就需要加入很多\,为了化简#python允许用r表示内部的字符串默认不转义print(r"C:\Users\Administrator\Desktop\学习")#加r打印出C:\Users\Administrator\Desktop\学习

#eval(str)#功能：将字符串str当成有效的表达式来求值并返回计算结果num1=eval("123")print(num1)#结果123print(type(num1))#<class ‘int‘>eval把字符串变为整数类型,跟int方式相同print(eval("+123"))#123print(eval("12+3")) #15print(int(12+3))    #15#print(eval("12ad"))   #出错

#len(str)#返回字符串的长度（字符个数）print(len("ong is a good"))

#lower()转换字符串中大写字母为小写字母#格式：str.lower()str15="ONG IS a good"print(str15.lower())  #ong is a goodprint("str15=%s" %(str15))

#upper(str)转换字符串中小写字母为大写字母str15="ONG IS a good"print(str15.upper())  #  ONG IS A GOOD#swapcase() 转换字符串中小写字母为大写字母,大写字母变小写字母str15="ONG IS a good"print(str15.swapcase())  #ong is A GOOD

#capitalize()一段文字中首字母大写，其他小写str15="ONG IS a good"print(str15.capitalize()) #Ong is a good

#title()每个单词的首字母大写,其他变小写str15="ONG IS a good"print(str15.title()) # Ong Is A Good

#center(width,fillchar)居中对齐，width为 要求宽度，fillchar是填充字符串str15="ONG IS a good"print(str15.center(40,"*"))#*************ONG IS a good**************

#ljust(width[,fillchar])左对齐，fillchar是填充的字符str15="ONG IS a good"print(str15.ljust(40))#ONG IS a goodprint(str15.ljust(40),"*") #ONG IS a good                            *print(str15.ljust(40,"*"))#ONG IS a good***************************

#rjust(width,fillchar)右对齐

原文地址：https://www.cnblogs.com/zlong123/p/10420641.html