def PickUpValue(dat,varnam):
    """ Return string just after 'varnam' and before ',' in 'dat'.
    
    :param str dat: data string
    :param str varnam: string
    :return: 'varnam'
    :rtype: str
    """
    value=''
    nv=len(varnam)
    ist=dat.find(varnam)
    if ist >= 0: value=dat[ist+nv:]
    ied=value.find(',')
    if ied >= 0: value=value[:ied]
    return value