持续更新：Python-string函数例子

#P48
import string;
str_old="this Is test";
str_space=" this Is test ";
str_tab="this\tIs test";
str_split="this,Is,test,programe";
str_num="123456";
str_numandstr="a1234";
str_notnumandstr="a123!4";
str_string="allstring";
str_space=" ";
str_tab="\t";
print("原始字符串:",str_old);
print("================================================================");
#全部转换成小写
print("lower:",str_old.lower());

#全部大写
print("upper:",str_old.upper());
#大小写互换
print("swapcase:",str_old.swapcase());

#首字母大写
print("capitalize:",str_old.capitalize());

#只有首字母大写，其余为小写
print("title:",str_old.title());

#在它把 字符串 用split()函数分开，然后用capitalize()把首字母变成大写，最后用join()合并到一起
print(string.capwords("this is String.capwordsd","==="));

#输出width个字符，S字符障蔽30位，左边不足部分用fillchar填充，默认的为空格。
#S.ljust(width,[fillchar])
print("ljust:",str_old.ljust(30,"-"));

#输出width个字符，S字符障蔽30位，不足部分用fillchar填充，中间对齐 填充默认的为空格
#S.center(width, [fillchar])

print("center:",str_old.center(30,"-"));

#输出width个字符，S字符障蔽30位，右边不足部分用fillchar填充，默认的为空格。
#S.rjust(width,[fillchar])
print("rjust:",str_old.rjust(30,"-"));

#输出width个字符，并在右对齐，不足部分用0补足
#S.center(width, [fillchar])
print("zfill:",str_old.zfill(30));

#返回S中出现substr的第一个字母的标号，如果S中没有substr则返回-1。start和end作用就相当于在S[start:end]中搜索
#S.find(substr, [start, [end]])
print("================================================================");
print("find:",str_old.find("is"));
print("find，指定STAR:",str_old.find("is",3));
print("find，指定STAR和END:",str_old.find("is",0,5));
print("================================================================");
#S.index(substr, [start, [end]])
#与find()相同，只是在S中没有substr时，会返回一个运行时错误
print("================================================================");
print("index:",str_old.index("s"));
print("index，指定STAR:",str_old.index("s",5));
print("index，指定STAR和END:",str_old.index("s",0,5));
print("================================================================");
#S.rfind(substr, [start, [end]])
#返回S中最后出现的substr的第一个字母的标号，如果S中没有substr则返回-1，也就是说从右边算起的第一次出现的substr的首字母标号
print("================================================================");
print("rfind:",str_old.rfind("s"));
print("rfind，指定STAR:",str_old.rfind("s",5));
print("rfind，指定STAR和END:",str_old.rfind("s",0,5));
print("================================================================");
#S.count(substr, [start, [end]])
#计算substr在S中出现的次数
print("================================================================");
print("count:",str_old.count("s"));
print("count，指定STAR:",str_old.count("s",5));
print("count，指定STAR和END:",str_old.count("s",0,5));
print("================================================================");
#S.replace(oldstr, newstr, [count])
#把S中的oldstar替换为newstr，count为替换次数。这是替换的通用形式，还有一些函数进行特殊字符的替换
print("================================================================");
print("replace:",str_old.replace("s","替换s"));
print("replace，指定次数-2:",str_old.replace("s","替换s2次",2));
print("================================================================");
#S.strip([chars])
#把S中前后chars中有的字符全部去掉，可以理解为把S前后chars替换为None
print("================================================================");
print("strip:",str_space.strip());
print("strip，指定替换字符:",str_space.strip("t"));
print("================================================================");
#把S中前chars中有的字符全部去掉，可以理解为把S前后chars替换为None
print("================================================================");
print("lstrip:",str_space.lstrip());
print("lstrip，指定替换字符:",str_space.lstrip("t"));
print("================================================================");
#把S中后chars中有的字符全部去掉，可以理解为把S前后chars替换为None
print("================================================================");
print("rstrip:",str_space.rstrip());
print("rstrip，指定替换字符:",str_space.rstrip("t"));
print("================================================================");
#S.expandtabs([tabsize])
#把S中的tab字符替换没空格，每个tab替换为tabsize个空格，默认是8个
print("expandtabs:",str_tab.expandtabs(30));
#S.split([sep, [maxsplit]])
#以sep为分隔符，把S分成一个list。maxsplit表示分割的次数。默认的分割符为空白字符即空格
print("================================================================");
print("split:",str_split.split());
print("split',':",str_split.split(","));
print("split','分隔2次:",str_split.split(",",2));
print("================================================================");
#S.splitr([sep, [maxsplit]])
#从右边开始分隔
print("================================================================");
print("rsplit:",str_split.rsplit());
print("rsplit',':",str_split.rsplit(","));
print("rsplit','分隔2次:",str_split.rsplit(",",2));
print("================================================================");
#S.join(seq)
#把seq代表的序列──字符串序列，用S连接起来
print("join:",str_split.join({"-","join","-","string"}));
#S.encode([encoding,[errors]])
# 其中encoding可以有多种值，比如gb2312 gbk gb18030 bz2 zlib big5 bzse64等都支持。
#errors默认值为"strict"，意思是UnicodeError。
#可能的值还有'ignore', 'replace', 'xmlcharrefreplace', 'backslashreplace'
#和所有的通过codecs.register_error注册的值。
str_code="test-code";
print("encode:",str_code.encode("gb18030","ignore"));
#S.startswith(prefix[,start[,end]]) ,endswith与startswith类似
#是否以prefix开头
print("================================================================");
print("startwith:",str_old.startswith("th"));
print("startwith，指定STAR:",str_old.startswith("th",5));
print("startwith，指定STAR和END:",str_old.startswith("th",5,8));
print("================================================================");
#S.isalnum()
#是否全是字母和数字，并至少有一个字符
print("================================================================");
print("isalnum（纯数字）:",str_num.isalnum());
print("isalnum（字母及数字）:",str_numandstr.isalnum());
print("isalnum（字母及数字及特殊字符）:",str_notnumandstr.isalnum());
print("================================================================");
#S.isalpha()
#是否全是字母，并至少有一个字符
print("================================================================");
print("isalpha（纯字母）:",str_string.isalpha());
print("isalpha（字母及数字）:",str_numandstr.isalpha());
print("================================================================");
#S.isdigit()
#是否全是数字，并至少有一个字符
print("================================================================");
print("isdigit（纯数字）:",str_num.isdigit());
print("isdigit（字母及数字）:",str_numandstr.isdigit());
print("isdigit（字母及数字及特殊字符）:",str_notnumandstr.isdigit());
print("================================================================");
#S.isspace()
#是否全是空白字符，并至少有一个字符
print("isspace（空格字符串）:",str_space.isspace());
print("isspace（TAB字符串）:",str_tab.isspace());
print("isspace（字母及数字及特殊字符）:",str_notnumandstr.isspace());
#S.islower()
#S中的字母是否全是小写,S.isupper()，S.istitle()与此类似
print("islower（全为小写）test:","test".isspace());
print("islower（全为大写）TEST:","TEST".isspace());
print("islower（大小写混合）:Test","Test".isspace());
print("islower（小写+特殊字符）test!:","test!".isspace());
print("islower（大写+特殊字符）TEST!:","TEST!".isspace());
print("islower（大写+小写+特殊字符）Test!:","Test!".isspace());

#string.atoi(s[,base])
#base默认为10，如果为0,那么s就可以是012或0x23这种形式的字符串，如果是16那么s就只能是0x23或0X12这种形式的字符串
#string.atol(s[,base]) #转成long
#string.atof(s[,base]) #转成float