当值满足ifelse的条件时，我尝试从okresy提取索引。以下结果表明，lapply循环让我感到困惑。什么是这些提升的大数字，以及如何从列表中提取每个向量中的索引？
okresy <- list(okres96, okres97, okres98, okres99, okres00, okres01, okres02, okres03, okres04, okres05, okres06, okres07, okres08, okres09, okres10, okres11, okres12, okres13, okres14, okres15, okres16, okres17)
day1 <- "1996-05-31"
day2 <- "2012-05-02"
day1 <- as.Date(day1, "%Y-%m-%d")
day2 <- as.Date(day2, "%Y-%m-%d")
values <- lapply(okresy, function(x) ifelse(day1 <= x & x <= day2, x, 0))
values
结果：
[[1]]
[1] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[35] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[69] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[103] 0 0 9647 9650 9651 9652 9654 9657 9658 9659 9660 9661 9664 9665 9666 9667 9668 9671 9672 9673 9674 9675 9678 9679 9680 9681 9682 9685 9686 9687 9688 9689 9692 9693
[137] 9694 9695 9696 9699 9700 9701 9702 9703 9706 9707 9708 9709 9710 9713 9714 9715 9716 9717 9720 9721 9722 9724 9727 9728 9729 9730 9731 9734 9735 9736 9737 9738 9741 9742
[171] 9743 9744 9745 9748 9749 9750 9751 9752 9755 9756 9757 9758 9759 9762 9763 9764 9765 9766 9769 9770 9771 9772 9773 9776 9777 9778 9779 9780 9783 9784 9785 9786 9787 9790
[205] 9791 9792 9793 9794 9797 9798 9799 9800 9804 9805 9806 9807 9808 9812 9813 9814 9815 9818 9819 9820 9821 9822 9825 9826 9827 9828 9829 9832 9833 9834 9835 9836 9839 9840
[239] 9841 9842 9843 9846 9847 9848 9849 9850 9853 9854 9860 9861
[[2]]
[1] 9863 9864 9867 9868 9869 9870 9871 9874 9875 9876 9877 9878 9881 9882 9883 9884 9885 9888 9889 9890 9891 9892 9895 9896 9897 9898 9899 9902
[29] 9903 9904 9905 9906 9909 9910 9911 9912 9913 9916 9917 9918 9919 9920 9923 9924 9925 9926 9927 9930 9931 9932 9933 9934 9937 9938 9939 9940
[57] 9941 9944 9945 9946 9947 9948 9952 9953 9954 9955 9958 9959 9960 9961 9962 9965 9966 9967 9968 9969 9972 9973 9974 9975 9976 9979 9980 9981
[85] 9986 9987 9988 9989 9990 9993 9994 9995 9996 9997 10000 10001 10002 10003 10004 10007 10008 10009 10011 10014 10015 10016 10017 10018 10021 10022 10023 10024
[113] 10025 10028 10029 10030 10031 10032 10035 10036 10037 10038 10039 10042 10043 10044 10045 10046 10049 10050 10051 10052 10053 10056 10057 10058 10059 10060 10063 10064
[141] 10065 10066 10067 10070 10071 10072 10073 10074 10077 10078 10079 10080 10081 10084 10085 10086 10087 10091 10092 10093 10094 10095 10098 10099 10100 10101 10102 10105
[169] 10106 10107 10108 10109 10112 10113 10114 10115 10116 10119 10120 10121 10122 10123 10126 10127 10128 10129 10130 10133 10134 10135 10136 10137 10140 10141 10142 10143
[197] 10144 10147 10148 10149 10150 10151 10154 10155 10156 10157 10158 10161 10162 10163 10164 10165 10168 10169 10170 10171 10172 10177 10178 10179 10182 10183 10184 10185
[225] 10186 10189 10190 10191 10192 10193 10196 10197 10198 10199 10200 10203 10204 10205 10206 10207 10210 10211 10212 10213 10214 10217 10218 10219 10224 10225 10226
(...)